Matrix Multiply Accelerator for Variable Bitwidth Operands

ABSTRACT

A processor, computer based method and apparatus for performing matrix multiplication are provided. The processor obtains a first bitslice vector comprising m elements, obtains a second bitslice vector comprising n elements, provides at least one element of the first bitslice vector as a first input to a single bit dot product unit, provides at least one element of the second bit-slice vector as a second input to the single-bit dot product unit, and obtains, from the single-bit dot product unit, an output comprising at least a partial dot product of the first and second bitslice vectors.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent application Ser. No. 17/493,420, filed on Oct. 4, 2021, the content of which is incorporated herein by reference in its entirety.

BACKGROUND

The present disclosure relates to computer systems. More particularly, the present disclosure relates to a matrix multiplication system and method.

Artificial neural networks (ANNs), such as deep neural networks (DNNs), convolutional neural networks (CNNs), etc., are a popular solution to a wide array of challenging classification, recognition and regression problems. However, many ANN models require a large number of calculations involving a large number of weights and activations, which presents a significant challenge with respect to access, storage and performance, particularly for mobile and other power or storage-constrained devices. An ANN hardware accelerator accelerates these calculations, such as, for example, convolution operations performed by CNNs.

Typically, native convolution operations are not performed by a CNN due to the complicated dataflow and expensive datapaths that are usually required. Instead, native convolution operations are converted into generic matrix multiplication (GEMM) operations, and then the GEMM operations are executed more efficiently using optimized software libraries for a processor or specialized hardware, such as, for example, a matrix multiply accelerator (MMA), etc. More particularly, an “IM2COL” software function may be used to convert the filter (weight) matrix and the input feature map (IFM) matrix for each convolution operation into an expanded format that is compatible with a GEMM operation. The IM2COL versions of each filter (weight) matrix and each IFM matrix are generated and stored in memory, and then loaded from memory and processed by the GEMM operation by the processor, MMA, etc.

However, different matrices may store data having different bit-widths. Unfortunately, MMAs use fixed-resolution MAC units regardless of the bit-width of the operands in order to maximize power and area efficiency.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts an ANN, in accordance with embodiments of the present disclosure.

FIG. 2 depicts a CNN, in accordance with embodiments of the present disclosure.

FIG. 3A depicts convolutional layer calculation for a CNN, FIG. 3B depicts a converted convolutional layer calculation for a CNN, and FIG. 3C depicts a converted input data matrix, in accordance with an embodiment of the present disclosure.

FIG. 4 depicts a data flow diagram for a multiply-and-accumulate (MAC) array.

FIG. 5 depicts the computation of the dot product between vector A and vector B using a MAC unit, in accordance with an embodiment of the present disclosure.

FIG. 6A depicts the creation of bitslice vectors from the vector A depicted in FIG. 5 , in accordance with an embodiment of the present disclosure.

FIG. 6B depicts the creation of bitslice vectors from the vector B depicted in FIG. 5 , in accordance with an embodiment of the present disclosure.

FIG. 6C depicts the computation of the dot product between two bitslice vectors using a one-bit dot product unit, in accordance with an embodiment of the present disclosure.

FIGS. 7A to 7F depict examples of the computation of the dot product between vector A and vector B using a one-bit dot product unit, in accordance with an embodiment of the present disclosure.

FIGS. 8A and 8B depict the creation of a bitslice tensor from a matrix X, in accordance with an embodiment of the present disclosure.

FIGS. 8C and 8D depict the creation of a bitslice tensor from a matrix Y, in accordance with an embodiment of the present disclosure.

FIGS. 9A and 9B depict data flow diagrams for an OBDP array, while FIG. 9C depicts an OBDP unit, in accordance with embodiments of the present disclosure.

FIGS. 10A to 10L depict examples of the multiplication of matrix X and matrix Y to generate matrix Z using an OBDP array, in accordance with an embodiment of the present disclosure.

FIG. 11 depicts a block diagram of an MMA, in accordance with embodiments of the present disclosure.

FIG. 12 depicts a block diagram of system, in accordance with an embodiment of the present disclosure.

DETAILED DESCRIPTION

Embodiments of the present disclosure will now be described with reference to the drawing figures, in which like reference numerals refer to like parts throughout.

Embodiments of the present disclosure provide a processor, computer-based method and apparatus for performing matrix multiplication. The processor obtains a first bitslice vector comprising m elements, obtains a second bitslice vector comprising n elements, provides at least one element of the first bitslice vector as a first input to a single bit dot product unit, provides at least one element of the second bit-slice vector as a second input to the single-bit dot product unit, and obtains, from the single-bit dot product unit, an output comprising a partial dot product or a dot product of the first and second bitslice vectors.

An ANN models the relationships between input data or signals and output data or signals using a network of interconnected nodes that is trained through a learning process. The nodes are arranged into various layers, including, for example, an input layer, one or more hidden layers, and an output layer. The input layer receives input data, such as, for example, image data, and the output layer generates output data, such as, for example, a probability that the image data contains a known object. Each hidden layer provides at least a partial transformation of the input data to the output data. A DNN has multiple hidden layers in order to model complex, nonlinear relationships between input data and output data.

In a fully-connected, feedforward ANN, each node is connected to all of the nodes in the preceding layer, as well as to all of the nodes in the subsequent layer. For example, each input layer node is connected to each hidden layer node, each hidden layer node is connected to each input layer node and each output layer node, and each output layer node is connected to each hidden layer node. Additional hidden layers are similarly interconnected. Each connection has a weight value, and each node has an activation function, such as, for example, a linear function, a step function, a sigmoid function, a tan h function, a rectified linear unit (ReLU) function, etc., that determines the output of the node based on the weighted sum of the inputs to the node. The input data propagates from the input layer nodes, through respective connection weights to the hidden layer nodes, and then through respective connection weights to the output layer nodes.

More particularly, at each input node, input data is provided to the activation function for that node, and the output of the activation function is then provided as an input data value to each hidden layer node. At each hidden layer node, the input data value received from each input layer node is multiplied by a respective connection weight, and the resulting products are summed or accumulated into an activation value that is provided to the activation function for that node. The output of the activation function is then provided as an input data value to each output layer node. At each output layer node, the output data value received from each hidden layer node is multiplied by a respective connection weight, and the resulting products are summed or accumulated into an activation value that is provided to the activation function for that node. The output of the activation function is then provided as output data. Additional hidden layers may be similarly configured to process data.

FIG. 1 depicts ANN 10, in accordance with an embodiment of the present disclosure.

ANN 10 includes input layer 20, one or more hidden layers 30, 40, 50, etc., and output layer 60. Input layer 20 includes one or more input nodes 21, 22, 23, etc. Hidden layer 30 includes one or more hidden nodes 31, 32, 33, 34, 35, etc. Hidden layer 40 includes one or more hidden nodes 41, 42, 43, 44, 45, etc. Hidden layer 50 includes one or more hidden nodes 51, 52, 53, 54, 55, etc. Output layer 60 includes one or more output nodes 61, 62, etc. Generally, ANN 10 includes N hidden layers, input layer 20 includes “i” nodes, hidden layer 30 includes “j” nodes, hidden layer 40 includes “k” nodes, hidden layer 50 includes “m” nodes, and output layer 60 includes “o” nodes.

In one embodiment, N equals 3, i equals 3, j, k and m equal 5 and o equals 2 (depicted in FIG. 1 ). Input node 21 is coupled to hidden nodes 31 to 35, input node 22 is coupled to hidden nodes 31 to 35, and input node 23 is coupled to hidden nodes 31 to 35. Hidden node 31 is coupled to hidden nodes 41 to 45, hidden node 32 is coupled to hidden nodes 41 to 45, hidden node 33 is coupled to hidden nodes 41 to 45, hidden node 34 is coupled to hidden nodes 41 to 45, and hidden node 35 is coupled to hidden nodes 41 to 45. Hidden node 41 is coupled to hidden nodes 51 to 55, hidden node 42 is coupled to hidden nodes 51 to 55, hidden node 43 is coupled to hidden nodes 51 to 55, hidden node 44 is coupled to hidden nodes 51 to 55, and hidden node 45 is coupled to hidden nodes 51 to 55. Hidden node 51 is coupled to output nodes 61 and 62, hidden node 52 is coupled to output nodes 61 and 62, hidden node 53 is coupled to output nodes 61 and 62, hidden node 54 is coupled to output nodes 61 and 62, and hidden node 55 is coupled to output nodes 61 and 62.

Many other variations of input, hidden and output layers are clearly possible, including hidden layers that are locally-connected, rather than fully-connected, to one another.

Training an ANN includes optimizing the connection weights between nodes by minimizing the prediction error of the output data until the ANN achieves a particular level of accuracy. One method is backpropagation, or backward propagation of errors, which iteratively and recursively determines a gradient descent with respect to the connection weights, and then adjusts the connection weights to improve the performance of the network.

A multi-layer perceptron (MLP) is a fully-connected ANN that has an input layer, an output layer and one or more hidden layers. MLPs may be used for natural language processing applications, such as machine translation, speech recognition, etc. Other ANNs include recurrent neural networks (RNNs), long short-term memories (LSTMs), sequence-to-sequence models that include an encoder RNN and a decoder RNN, shallow neural networks, etc.

A CNN is a variation of an MLP that may be used for classification or recognition applications, such as image recognition, speech recognition, etc. A CNN has an input layer, an output layer and multiple hidden layers including convolutional layers, pooling layers, normalization layers, fully-connected layers, etc. Each convolutional layer applies a sliding dot product or cross-correlation to an input volume, applies an activation function to the results, and then provides the activation or output volume to the next layer. Convolutional layers typically use the ReLU function as the activation function. In certain embodiments, the activation function is provided in a separate activation layer, such as, for example, a ReLU layer. A pooling layer reduces the dimensions of the output volume received from the preceding convolutional layer, and may calculate an average or a maximum over small clusters of data, such as, for example, 2×2 matrices. In certain embodiments, a convolutional layer and a pooling layer may form a single layer of a CNN. The fully-connected layers follow the convolutional and pooling layers, and include a flatten layer and a classification layer, followed by a normalization layer that includes a normalization function, such as the SoftMax function. The output layer follows the last fully-connected layer; in certain embodiments, the output layer may include the normalization function.

FIG. 2 depicts CNN 100, in accordance with an embodiment of the present disclosure. CNN 100 includes input layer 120, one or more hidden layers, such as convolutional layer 130-1, pooling layer 130-2, hidden (flatten) layer 140, hidden (classification) layer 150, etc., and output layer 160. Many other variations of input, hidden and output layers are contemplated.

Input layer 120 includes one or more input nodes 121, etc., that present the input data, such as a color image, as an input volume to the first convolutional layer, e.g., convolutional layer 130-1. The input volume is a three-dimensional matrix that has a height (1^(st) dimension or number of rows), a width (2^(nd) dimension or number of columns) and a depth (3^(rd) dimension). For example, input data that represent a color image are presented as an input volume that is 512 pixels×512 pixels×3 channels (red, green, blue); other input volume dimensions may also be used, such as 32×32×3, 64×64×3, 128×128×3, etc., 32×32×1, 64×64×1, 128×128×1, 512×512×1, etc.

Convolutional layer 130-1 is locally-connected to input layer 120, and includes a plurality of nodes that are connected to local regions in the input volume (not depicted for clarity). For a CNN that uses a standard convolution, each node computes a dot product between the node's weights and the respective local region of the input volume. An activation function is then applied to the results of each convolution calculation to produce an output volume that is provided as an input volume to the subsequent layer. The activation function may be applied by each convolutional layer node or by the nodes of a subsequent locally-connected ReLU layer.

Pooling layer 130-2 is locally-connected to convolutional layer 130-1, and includes a plurality of nodes that are connected to local regions in the input volume (not depicted for clarity). Pooling layer 130-2 also produces an output volume that is provided as the input volume to the subsequent layer, such as, for example, another convolutional layer 130-1, a flatten layer 140, etc. In certain embodiments, convolutional layer 130-1 and pooling layer 130-2 form a single hidden layer 130. Similarly, in certain embodiments, convolutional layer 130-1, a ReLU layer and pooling layer 130-2 form a single hidden layer 130. Generally, the output volumes of the convolutional and pooling layers may be described as feature maps, and one or more single hidden layers 130 form a feature learning portion of CNN 100.

Hidden layer 140 is a “flatten” layer that is locally-connected to pooling layer 130-2, and includes one or more hidden (flatten) nodes 141, 142, 143, 144, 145, etc. Hidden (flatten) layer 140 “flattens” the output volume produced by the preceding pooling layer 130-2 into a column vector, which is provided to the subsequent, fully-connected hidden layer 150.

Hidden layer 150 is a classification layer that is fully-connected to hidden (flatten) layer 140, and includes one or more hidden (classification) nodes 151, 152, 153, 154, 155, etc.

Output layer 160 includes one or more output nodes 161, 162, etc., and is fully-connected to hidden (classification) layer 150. Fully-connected output layer 160 receives the classification results output by hidden (classification) layer 150, and each node outputs a predicted class score. A normalization function, such as a SoftMax function, may be applied to the predicted class scores by output layer 160, or, alternatively, by an additional layer interposed between hidden (classification) layer 150 and output layer 160.

Similar to ANNs, training a CNN includes optimizing the connection weights between nodes by minimizing the prediction error of the output data until the CNN achieves a particular level of accuracy. As noted above, backpropagation may be used to iteratively and recursively determines a gradient descent with respect to the connection weights, and then adjusts the connection weights to improve the performance of the network. Matrix multiplication operations, and, more particularly, multiply-and-accumulate (MAC) operations, are used extensively by CNNs, as well as other ANNs.

FIG. 3A depicts convolutional layer calculation 200 for a CNN, in accordance with an embodiment of the present disclosure.

Input feature maps 204 include four channels and one input data matrix for each channel, i.e., input data matrices 204 ¹, 204 ², 204 ³ and 204 ⁴. Filter 202 includes four filter or weight sets 202 ¹, 202 ², 202 ³ and 202 ⁴, and each filter or weight set includes four weight matrices, one weight matrix for each channel. Output feature maps 206 include four channels and one output data matrix for each filter or weight set, i.e., output data matrices 206 ¹, 206 ², 206 ³ and 206 ⁴. Convolutional layer calculation 200 convolves filter 202 with input feature maps 204 to produce output feature maps 206.

Generally, input data matrices 204 ¹, 204 ², 204 ³ and 204 ⁴ form an input tensor, each weight set 202 ¹, 202 ², 202 ³ and 202 ⁴ forms a weight tensor, and output data matrices 206 ¹, 206 ², 206 ³ and 206 ⁴ form an output tensor. In this embodiment, each tensor has a height (1^(st) dimension or number of rows), a width (2^(nd) dimension or number of columns) and a depth (3^(rd) dimension). The depth of the input tensor is equal to the number of channels, the depth of each weight tensor is equal to the number of channels, and the depth of the output tensor is equal to the number of weight tensors (i.e., weight sets). While particular dimensions for the tensors and matrices have been selected for clarity of illustration and explanation, embodiments of the present disclosure are not so limited.

In one embodiment, input data matrix 204 ¹ is a 5×5 matrix (i.e., 5 rows and 5 columns) associated with the first channel and includes activations a¹ ₁, a¹ ₂, a¹ ₃, a¹ ₄, a¹ ₅, a¹ ₆, a¹ ₇, a¹ ₈, a¹ ₉, a¹ ₁₀, a¹ ₁₁, a¹ ₁₂, a¹ ₁₃, a¹ ₁₄, a¹ ₁₅, a¹ ₁₆, a¹ ₁₇, a¹ ₁₈, a¹ ₁₉, a¹ ₂₀, a¹ ₂₁, a¹ ₂₂, a¹ ₂₃, a¹ ₂₄ and a¹ ₂₅. Input data matrix 204 ² is a 5×5 matrix associated with the second channel and includes activations a² ₁, a² ₂, a² ₃, a² ₄, a² ₅, a² ₆, a² ₇, a² ₈, a² ₉, a² ₁₀, a² ₁₂, a² ₁₃, a² ₁₄, a² ₁₅, a² ₁₆, a² ₁₇, a² ₁₈, a² ₁₉, a² ₂₀, a² ₂₁, a² ₂₂, a² ₂₃, a² ₂₄ and a² ₂₅. Input data matrix 204 ³ is a 5×5 matrix associated with the third channel and includes activations a³ ₁, a³ ₂, a³ ₃, a³ ₄, a³ ₅, a³ ₆, a³ ₇, a³ ₈, a³ ₉, a³ ₁₀, a³ ₁₁, a³ ₁₂, a³ ₁₃, a³ ₁₄, a³ ₁₅, a³ ₁₆, a³ ₁₇, a³ ₁₈, a³ ₁₉, a³ ₂₀, a³ ₂₁, a³ ₂₂, a³ ₂₃, a³ ₂₄ and a³ ₂₅. Input data matrix 204 ⁴ is a 5×5 matrix associated with the fourth channel and includes activations a⁴ ₁, a⁴ ₂, a⁴ ₃, a⁴ ₄, a⁴ ₅, a⁴ ₆, a⁴ ₇, a⁴ ₈, a⁴ ₉, a⁴ ₁₀, a⁴ ₁₁, a⁴ ₁₂, a⁴ ₁₃, a⁴ ₁₄, a⁴ ₁₅, a⁴ ₁₆, a⁴ ₁₇, a⁴ ₁₈, a⁴ ₁₉, a⁴ ₂₀, a⁴ ₂₁, a⁴ ₂₂, a⁴ ₂₃, a⁴ ₂₄ and a⁴ ₂₅.

In this embodiment, weight set 202 ¹ includes four weight matrices 202 ¹ ₁, 202 ¹ ₂, 202 ¹ ₃ and 202 ¹ ₄. Weight matrix 202 ¹ ₁ is a 2×2 matrix (i.e., 2 rows and 2 columns) associated with the first channel, and includes weights w¹ ₁, w¹ ₂, w¹ ₃ and w¹ ₄. Weight matrix 202 ¹ ₂ is a 2×2 matrix associated with the second channel, and includes weights w¹ ₅, w¹ ₆, w¹ ₇ and w¹ ₈. Weight matrix 202 ¹ ₃ is a 2×2 matrix associated with the third channel, and includes weights w¹ ₉, w¹ ₁₀, w¹ ₁₁ and w¹ ₁₂. Weight matrix 202 ¹ ₄ is a 2×2 matrix associated with the fourth channel, and includes weights w¹ ₁₃, w¹ ₁₄, w¹ ₁₅ and w¹ ₁₆.

Weight set 202 ² includes four weight matrices 202 ² ₁, 202 ² ₂, 202 ² ₃ and 202 ² ₄. Weight matrix 202 ² ₁ is a 2×2 matrix associated with the first channel, and includes weights w² ₁, w² ₂, w² ₃ and w² ₄. Weight matrix 202 ² ₂ is a 2×2 matrix associated with the second channel, and includes weights w² ₅, w² ₆, w² ₇ and w² ₈. Weight matrix 202 ² ₃ is a 2×2 matrix associated with the third channel, and includes weights w² ₉, w² ₁₀, w² ₁₁ and w² ₁₂. Weight matrix 202 ² ₄ is a 2×2 matrix associated with the fourth channel, and includes weights w² ₁₃, w² ₁₄, w² ₁₅ and w² ₁₆.

Weight set 202 ³ includes four weight matrices 202 ³ ₁, 202 ³ ₂, 202 ³ ₃ and 202 ³ ₄. Weight matrix 202 ³ ₁ is a 2×2 matrix associated with the first channel, and includes weights w³ ₁, w³ ₂, w³ ₃ and w³ ₄. Weight matrix 202 ³ ₂ is a 2×2 matrix associated with the second channel, and includes weights w³ ₅, w³ ₆, w³ ₇ and w³ ₈. Weight matrix 202 ³ ₃ is a 2×2 matrix associated with the third channel, and includes weights w³ ₉, w³ ₁₀, w³ ₁₁ and w³ ₁₂. Weight matrix 202 ³ ₄ is a 2×2 matrix associated with the fourth channel, and includes weights w³ ₁₃, w³ ₁₄, w³ ₁₅ and w³ ₁₆.

Weight set 202 ⁴ includes four weight matrices 202 ⁴ ₁, 202 ⁴ ₂, 202 ⁴ ₃ and 202 ⁴ ₄. Weight matrix 202 ⁴ ₁ is a 2×2 matrix associated with the first channel, and includes weights w⁴ ₁, w⁴ ₂, w⁴ ₃ and w⁴ ₄. Weight matrix 202 ⁴ ₂ is a 2×2 matrix associated with the second channel, and includes weights w⁴ ₅, w⁴ ₆, w⁴ ₇ and w⁴ ₈. Weight matrix 202 ⁴ ₃ is a 2×2 matrix associated with the third channel, and includes weights w⁴ ₉, w⁴ ₁₀, w⁴ ₁₁ and w⁴ ₁₂. Weight matrix 202 ⁴ ₄ is a 2×2 matrix associated with the fourth channel, and includes weights w⁴ ₁₃, w⁴ ₁₄, w⁴ ₁₅ and w⁴ ₁₆.

In this embodiment, output data matrix 206 ¹ is a 4×4 matrix associated with weight set 202 ¹ and includes activations o¹ ₁, o¹ ₂, o¹ ₃, o¹ ₄, o¹ ₅, o¹ ₆, o¹ ₇, o¹ ₈, o¹ ₉, o¹ ₁₀, o¹ ₁₁, o¹ ₁₂, o¹ ₁₃, o¹ ₁₄, o¹ ₁₅ and o¹ ₁₆. Output data matrix 206 ² is a 4×4 matrix associated with weight set 202 ² and includes activations o² ₁, o² ₂, o² ₃, o² ₄, o² ₅, o² ₆, o² ₇, o² ₈, o² ₉, o² ₁₀, o² ₁₁, o² ₁₂, o² ₁₃, o² ₁₄, o² ₁₅ and o² ₁₆. Output data matrix 206 ³ is a 4×4 matrix associated with weight set 202 ³ and includes activations o³ ₁, o³ ₂, o³ ₃, o³ ₄, o³ ₅, o³ ₆, o³ ₇, o³ ₈, o³ ₉, o³ ₁₀, o³ ₁₁, o³ ₁₂, o³ ₁₃, o³ ₁₄, o³ ₁₅ and o³ ₁₆. Output data matrix 206 ⁴ is a 4×4 matrix associated with weight set 202 ⁴ and includes activations o⁴ ₁, o⁴ ₂, o⁴ ₃, o⁴ ₄, o⁴ ₅, o⁴ ₈, o⁴ ₇, o⁴ ₈, o⁴ ₉, o⁴ ₁₀, o⁴ ₁₁, o⁴ ₁₂, o⁴ ₁₃, o⁴ ₁₄, o⁴ ₁₅ and o⁴ ₁₆.

For ease of explanation, each input data matrix 204 ¹, 204 ², 204 ³ and 204 ⁴ may be divided into four quadrants. The first quadrant spans the top (first) row and the second row, the second quadrant spans the second row and the third row, the third quadrant spans the third row and the fourth row, and the fourth quadrant spans the fourth row and the fifth (bottom) row. The first quadrant for input data matrix 204 ¹ (a¹ _(q1)), the first quadrant for input data matrix 204 ² (a² _(q1)), the first quadrant for input data matrix 204 ³ (a³ _(q1)), and the first quadrant for input data matrix 204 ⁴ (a⁴ _(q1)) are depicted; the remaining three quadrants for each input data matrix are not depicted for clarity.

First quadrant a¹ _(q1) includes elements a¹ ₁, a¹ ₂, a¹ ₃, a¹ ₄, a¹ ₅, a¹ ₆, a¹ ₇, a¹ ₈, a¹ ₉ and a¹ ₁₀, from which four blocks of elements are formed, i.e., a first block (a¹ ₁, a¹ ₂, a¹ ₆ and a¹ ₇), a second block (a¹ ₂, a¹ ₃, a¹ ₇ and a¹ ₈), a third block (a¹ ₃, a¹ ₄, a¹ ₈ and a¹ ₉), and a fourth block (a¹ ₄, a¹ ₅, a¹ ₉ and a¹ ₁₀). First quadrant a² _(q1) includes elements a² ₁, a² ₂, a² ₃, a² ₄, a² ₅, a² ₆, a² ₇, a² ₈, a² ₉ and a² ₁₀, from which four blocks of elements are formed, i.e., a first block (a² ₁, a² ₂, a² ₆ and a² ₇), a second block (a² ₂, a² ₃, a² ₇ and a² ₈), a third block (a² ₃, a² ₄, a² ₈ and a² ₉), and a fourth block (a² ₄, a² ₅, a² ₉ and a² ₁₀). First quadrant a³ _(q1) includes elements a³ ₁, a³ ₂, a³ ₃, a³ ₄, a³ ₅, a³ ₆, a³ ₇, a³ ₈, a³ ₉ and a³ ₁₀, from which four blocks of elements are formed, i.e., a first block (a³ ₁, a³ ₂, a³ ₆ and a³ ₇), a second block (a³ ₂, a³ ₃, a³ ₇ and a³ ₈), a third block (a³ ₃, a³ ₄, a³ ₈ and a³ ₉), and a fourth block (a³ ₄, a³ ₅, a³ ₉ and a³ ₁₀). First quadrant a⁴ _(q1) includes elements a⁴ ₁, a⁴ ₂, a⁴ ₃, a⁴ ₄, a⁴ ₅, a⁴ ₆, a⁴ ₇, a⁴ ₈, a⁴ ₉ and a⁴ ₁₀, from which four blocks of elements are formed, i.e., a first block (a⁴ ₁, a⁴ ₂, a⁴ ₆ and a⁴ ₇), a second block (a⁴ ₂, a⁴ ₃, a⁴ ₇ and a⁴ ₈), a third block (a⁴ ₃, a⁴ ₄, a⁴ ₈ and a⁴ ₉), and a fourth block (a⁴ ₄, a⁴ ₅, a⁴ ₉ and a⁴ ₁₀).

Second quadrant a¹ _(q2) includes elements a¹ ₆, a¹ ₇, a¹ ₈, a¹ ₉, a¹ ₁₀, a¹ ₁, a¹ ₁₂, a¹ ₁₃, a¹ ₁₄ and a¹ ₁₅, from which four blocks of elements are formed, i.e., a first block (a¹ ₆, a¹ ₇, a¹ ₁₁ and a¹ ₁₂), a second block (a¹ ₇, a¹ ₈, a¹ ₁₂ and a¹ ₁₃), a third block (a¹ ₈, a¹ ₉, a¹ ₁₃ and a¹ ₁₄), and a fourth block (a¹ ₉, a¹ ₁₀, a¹ ₁₄ and a¹ ₁₅). Second quadrant a² _(q2) includes elements a² ₆, a² ₇, a² ₈, a² ₉, a² ₁₀, a² ₁₁, a² ₁₂, a² ₁₃, a² ₁₄ and a² ₁₅, from which four blocks of elements are formed, i.e., a first block (a² ₆, a² ₇, a² ₁₁ and a² ₁₂), a second block (a² ₇, a² ₈, a² ₁₂ and a² ₁₃), a third block (a² ₈, a² ₉, a² ₁₃ and a² ₁₄), and a fourth block (a² ₉, a² ₁₀, a² ₁₄ and a² ₁₅). Second quadrant a³ _(q2) includes elements a³ ₆, a³ ₇, a³ ₈, a³ ₉, a³ ₁₀, a³ ₁₁, a³ ₁₂, a³ ₁₃, a³ ₁₄ and a³ ₁₅, from which four blocks of elements are formed, i.e., a first block (a³ ₆, a³ ₇, and a³ ₁₂), a second block (a³ ₇, a³ ₈, a³ ₁₂ and a³ ₁₃), a third block (a³ ₈, a³ ₉, a³ ₁₃ and a³ ₁₄), and a fourth block (a³ ₉, a³ ₁₀, a³ ₁₄ and a³ ₁₅). Second quadrant a⁴ _(q2) includes elements a⁴ ₆, a⁴ ₇, a⁴ ₈, a⁴ ₉, a⁴ ₁₀, a⁴ ₁₁, a⁴ ₁₂, a⁴ ₁₃, a⁴ ₁₄ and a⁴ ₁₅, from which four blocks of elements are formed, i.e., a first block (a⁴ ₆, a⁴ ₇, a⁴ ₁₁ and a⁴ ₁₂), a second block (a⁴ ₇, a⁴ ₈, a⁴ ₁₂ and a⁴ ₁₃), a third block (a⁴ ₈, a⁴ ₉, a⁴ ₁₃ and a⁴ ₁₄), and a fourth block (a⁴ ₉, a⁴ ₁₀, a⁴ ₁₄ and a⁴ ₁₅).

Third quadrant a¹ _(q3) includes elements a¹ ₁₁, a¹ ₁₂, a¹ ₁₃, a¹ ₁₄, a¹ ₁₅, a¹ ₁₆, a¹ ₁₇, a¹ ₁₈, a¹ ₁₉ and a¹ ₂₀, from which four blocks of elements are formed, i.e., a first block (a¹ ₁₁, a¹ ₁₂, a¹ ₁₆ and a¹ ₁₇), a second block (a¹ ₁₂, a¹ ₁₃, a¹ ₁₇ and a¹ ₁₈), a third block (a¹ ₁₃, a¹ ₁₄, a¹ ₁₈ and a¹ ₁₉), and a fourth block (a¹ ₁₄, a¹ ₁₅, a¹ ₁₉ and a¹ ₂₀). Third quadrant a² ₀ includes elements a² ₁₁, a² ₁₂, a² ₁₃, a² ₁₄, a² ₁₅, a² ₁₆, a² ₁₇, a² ₁₈, a² ₁₉ and a² ₂₀, from which four blocks of elements are formed, i.e., a first block (a² ₁₁, a² ₁₂, a² ₁₆ and a² ₁₇), a second block (a² ₁₂, a² ₁₃, a² ₁₇ and a² ₁₈), a third block (a² ₁₃, a² ₁₄, a² ₁₈ and a² ₁₉), and a fourth block (a² ₁₄, a² ₁₅, a² ₁₉ and a² ₂₀). Third quadrant a³ ₀ includes elements a³ ₁₁, a³ ₁₂, a³ ₁₃, a³ ₁₄, a³ ₁₅, a³ ₁₆, a³ ₁₇, a³ ₁₈, a³ ₁₉ and a³ ₂₀, from which four blocks of elements are formed, i.e., a first block (a³ ₁₁, a³ ₁₂, a³ ₁₆ and a³ ₁₇), a second block (a³ ₁₂, a³ ₁₃, a³ ₁₇ and a³ ₁₈), a third block (a³ ₁₃, a³ ₁₄, a³ ₁₈ and a³ ₁₉), and a fourth block (a³ ₁₄, a³ ₁₅, a³ ₁₉ and a³ ₂₀). Third quadrant a⁴ _(q3) includes elements a⁴ ₁₁, a⁴ ₁₂, a⁴ ₁₃, a⁴ ₁₄, a⁴ ₁₅, a⁴ ₁₆, a⁴ ₁₇, a⁴ ₁₈, a⁴ ₁₉ and a⁴ ₂₀, from which four blocks of elements are formed, i.e., a first block (a⁴ ₁₁, a⁴ ₁₂, a⁴ ₁₆ and a⁴ ₁₇), a second block (a⁴ ₁₂, a⁴ ₁₃, a⁴ ₁₇ and a⁴ ₁₈), a third block (a⁴ ₁₃, a⁴ ₁₄, a⁴ ₁₈ and a⁴ ₁₉), and a fourth block (a⁴ ₁₄, a⁴ ₁₅, a⁴ ₁₉ and a⁴ ₂₀).

Fourth quadrant a¹ _(q4) includes elements a¹ ₁₆, a¹ ₁₇, a¹ ₁₈, a¹ ₁₉, a¹ ₂₀, a¹ ₂₁, a¹ ₂₂, a¹ ₂₃, a¹ ₂₄ and a¹ ₂₅, from which four blocks of elements are formed, i.e., a first block (a¹ ₁₆, a¹ ₁₇, a¹ ₂₁ and a¹ ₂₂), a second block (a¹ ₁₇, a¹ ₁₈, a¹ ₂₂ and a¹ ₂₃), a third block (a¹ ₁₈, a¹ ₁₉, a¹ ₂₃ and a¹ ₂₄), and a fourth block (a¹ ₁₉, a¹ ₂₀, a¹ ₂₄ and a¹ ₂₅). Fourth quadrant a² _(q4) includes elements a² ₁₆, a² ₁₇, a² ₁₈, a² ₁₉, a² ₂₀, a² ₂₁, a² ₂₂, a² ₂₃, a² ₂₄ and a² ₂₅, from which four blocks of elements are formed, i.e., a first block (a² ₁₆, a² ₁₇, a² ₂₁ and a² ₂₂), a second block (a² ₁₇, a² ₁₈, a² ₂₂ and a² ₂₃), a third block (a² ₁₈, a² ₁₉, a² ₂₃ and a² ₂₄), and a fourth block (a² ₁₉, a² ₂₀, a² ₂₄ and a² ₂₅). Fourth quadrant a³ _(q4) includes elements a³ ₁₆, a³ ₁₇, a³ ₁₈, a³ ₁₉, a³ ₂₀, a³ ₂₁, a³ ₂₂, a³ ₂₃, a³ ₂₄ and a³ ₂₅, from which four blocks of elements are formed, i.e., a first block (a³ ₁₆, a³ ₁₇, a³ ₂₁ and a³ ₂₂), a second block (a³ ₁₇, a³ ₁₈, a³ ₂₂ and a³ ₂₃), a third block (a³ ₁₈, a³ ₁₉, a³ ₂₃ and a³ ₂₄), and a fourth block (a³ ₁₉, a³ ₂₀, a³ ₂₄ and a³ ₂₅). Fourth quadrant a⁴ _(q4) includes elements a⁴ ₁₆, a⁴ ₁₇, a⁴ ₁₈, a⁴ ₁₉, a⁴ ₂₀, a⁴ ₂₁, a⁴ ₂₂, a⁴ ₂₃, a⁴ ₂₄ and a⁴ ₂₅, from which four blocks of elements are formed, i.e., a first block (a⁴ ₁₆, a⁴ ₁₇, a⁴ ₂₁ and a⁴ ₂₂), a second block (a⁴ ₁₇, a⁴ ₁₈, a⁴ ₂₂ and a⁴ ₂₃), a third block (a⁴ ₁₈, a⁴ ₁₉, a⁴ ₂₃ and a⁴ ₂₄), and a fourth block (a⁴ ₁₉, a⁴ ₂₀, a⁴ ₂₄ and a⁴ ₂₅).

Output feature maps 206 may also be divided into four quadrants; in this case, each quadrant spans all four output data matrices 206 ¹, 206 ², 206 ³ and 206 ⁴. The first quadrant spans the top (first) row of each output data matrix, the second quadrant spans the second row of each output data matrix, the third quadrant spans the third row of each output data matrix, and the fourth quadrant spans the fourth (bottom) row of each output data matrix. The first quadrant for output feature maps 206 (o_(q1)), is depicted; the remaining three quadrants are not depicted for clarity.

First quadrant o_(q1) includes o¹ ₁, o¹ ₂, o¹ ₃, o¹ ₄, o² ₁, o² ₂, o² ₃, o² ₄, o³ ₁, o³ ₂, o³ ₃, o³ ₄, o⁴ ₁, o⁴ ₂, o⁴ ₃ and o⁴ ₄. Second quadrant o_(q2) includes o¹ ₅, o¹ ₆, o¹ ₇, o¹ ₈, o² ₅, o² ₆, o² ₇, o² ₈, o³ ₅, o³ ₆, o³ ₇, o³ ₈, o⁴ ₅, o⁴ ₆, o⁴ ₇ and o⁴ ₈. Third quadrant o_(q3) includes o¹ ₉, o¹ ₁₀, o¹ ₁₁, o¹ ₁₂, o² ₉, o² ₁₀, o² ₁₁, o² ₁₂, o³ ₉, o³ ₁₀, o³ ₁₁, o³ ₁₂, o⁴ ₉, o⁴ ₁₀, o⁴ ₁₁ and o⁴ ₁₂. Fourth quadrant o_(q4) includes o¹ ₁₃, o¹ ₁₄, o¹ ₁₅, o¹ ₁₆, o² ₁₃, o² ₁₄, o² ₁₅, o² ₁₆, o³ ₁₃, o³ ₁₄, o³ ₁₅, o³ ₁₆, o⁴ ₁₃, o⁴ ₁₄, o⁴ ₁₅ and o⁴ ₁₆.

Generally, each output element within output data matrices 206 ¹, 206 ², 206 ³ and 206 ⁴ is the sum of the dot products of one of the weight sets 202 ¹, 202 ², 202 ³ and 202 ⁴ and a block of activation elements within a particular quadrant of input data matrices 204 ¹, 204 ², 204 ³ and 204 ⁴.

The calculation of the output elements in quadrant o_(q1) follows.

Output element o¹ ₁ of output data matrix 206 ¹ is the sum of the dot products of weight set 202 ¹ and the first block of activation elements within first quadrants a¹ _(q1), a² _(q1), a³ _(q1) and a⁴ _(q1) of input data matrices 204 ¹, 204 ², 204 ³ and 204 ⁴, respectively. The first block of activation elements within first quadrants a¹ _(q1), a² _(q1), a³ _(q1) and a⁴ _(q1) includes a¹ ₁, a¹ ₂, a¹ ₆ and a¹ ₇; a² ₁, a² ₂, a² ₆ and a² ₇; a³ ₁, a³ ₂, a³ ₆ and a³ ₇; and a⁴ ₁, a⁴ ₂, a⁴ ₆ and a⁴ ₇, respectively.

More particularly, the following dot products are summed to generate output element o¹ ₁: the dot product of the first weight matrix of weight set 202 ¹ and the first block of quadrant a¹ _(q1) (i.e., w¹ ₁·a¹ ₁+w¹ ₂·a¹ ₂·w¹ ₃·a¹ ₆+w¹ ₄·a¹ ₇), the dot product of the second weight matrix of weight set 202 ¹ and the first block of quadrant a² _(q1) (i.e., w¹ ₅·a² ₁+w¹ ₆·a² ₂+w¹ ₇·a² ₆+w¹ ₈·a² ₇), the dot product of the third weight matrix of weight set 202 ¹ and the first block of quadrant a³ _(q1) (i.e., w¹ ₉·a³ ₁+w¹ ₁₀·a³ ₂+w¹ ₁₁·a³ ₆+w¹ ₁₂·a³ ₇), and the dot product of the fourth weight matrix of weight set 202 ¹ and the first block of quadrant a⁴ _(q1) (i.e., w¹ ₁₃·a⁴ ₁+w¹ ₁₄·a⁴ ₂+w¹ ₁₅·a⁴ ₆+w¹ ₁₆·a⁴ ₇).

Similarly, output element o² ₁ of output data matrix 206 ² is the sum of the dot products of weight set 202 ² and the first block of activation elements within first quadrants a¹ _(q1), a² _(q1), a³ _(q1) and a⁴ _(q1) of input data matrices 204 ¹, 204 ², 204 ³ and 204 ⁴, respectively. Output element o³ ₁ of output data matrix 206 ³ is the sum of the dot products of weight set 202 ³ and the first block of activation elements within first quadrants a¹ _(q1), a² _(q1), a³ _(q1) and a⁴ _(q1) of input data matrices 204 ¹, 204 ², 204 ³ and 204 ⁴, respectively. And, output element o⁴ ₁ of output data matrix 206 ⁴ is the sum of the dot products of weight set 202 ⁴ and the first block of activation elements within first quadrants a¹ _(q1), a² _(q1), a³ _(q1) and a⁴ _(q1) of input data matrices 204 ¹, 204 ², 204 ³ and 204 ⁴, respectively.

Output element o¹ ₂ of output data matrix 206 ¹ is the sum of the dot products of weight set 202 ¹ and the second block of activation elements within the first quadrants a¹ _(q1), a² _(q1), a³ _(q1) and a⁴ _(q1) of input data matrices 204 ¹, 204 ², 204 ³ and 204 ⁴, respectively. The second block of activation elements within the first quadrants a¹ _(q1), a² _(q1), a³ _(q1) and a⁴ _(q1) includes a¹ ₂, a¹ ₃, a¹ ₇ and a¹ ₈; a² ₂, a² ₃, a² ₇ and a² ₈; a³ ₂, a³ ₃, a³ ₇ and a³ ₈; and a⁴ ₂, a⁴ ₃, a⁴ ₇ and a⁴ ₈, respectively.

More particularly, the following dot products are summed to generate output element o¹ ₂: the dot product of the first weight matrix of weight set 202 ¹ and the second block of quadrant a (i.e., w¹ ₁·a¹ ₂+w¹ ₂·a¹ ₃+w¹ ₃·a¹ ₇+w¹ ₄·a¹ ₈), the dot product of the second weight matrix of weight set 202 ¹ and the second block of quadrant a² _(q1) (i.e., w¹ ₅·a² ₂+w¹ ₆·a² ₃+w¹ ₇·a² ₇+w¹ ₈·a² ₈), the dot product of the third weight matrix of weight set 202 ¹ and the second block of quadrant a³ _(q1) (i.e., w¹ ₉·a³ ₂+w¹ ₁₀·a³ ₃+w¹ ₁₁·a³ ₇+w¹ ₁₂·a³ ₈), and the dot product of the fourth weight matrix of weight set 202 ¹ and the second block of quadrant a⁴ _(q1) (i.e., w¹ ₁₃·a⁴ ₂+w¹ ₁₄·a⁴ ₃+w¹ ₁₅·a⁴ ₇+w¹ ₁₆·a⁴ ₈).

Similarly, output element o² ₂ of output data matrix 206 ² is the sum of the dot products of weight set 202 ² and the second block of activation elements within first quadrants a¹ _(q1), a² _(q1), a³ _(q1) and a⁴ _(q1) of input data matrices 204 ¹, 204 ², 204 ³ and 204 ⁴, respectively. Output element o³ ₂ of output data matrix 206 ³ is the sum of the dot products of weight set 202 ³ and the second block of activation elements within first quadrants a¹ _(q1), a² _(q1), a³ _(q1) and a⁴ _(q1) of input data matrices 204 ¹, 204 ², 204 ³ and 204 ⁴, respectively. And, output element o⁴ ₂ of output data matrix 206 ⁴ is the sum of the dot products of weight set 202 ⁴ and the second block of activation elements within the quadrants a¹ _(q1), a² _(q1), a³ _(q1) and a⁴ _(q1) of input data matrices 204 ¹, 204 ², 204 ³ and 204 ⁴, respectively.

And so on for output elements o¹ ₃ and o¹ ₄, o² ₃ and o² ₄, o³ ₃ and o³ ₄, and o⁴ ₃ and o⁴ ₄ of the first rows of output data matrices 206 ¹, 206 ², 206 ³ and 206 ⁴.

With respect to quadrant o_(q2), output element o¹ ₅ of output data matrix 206 ¹ is the sum of the dot products of weight set 202 ¹ and the first block of activation elements within second quadrants a¹ _(q2), a² _(q2), a³ _(q2) and a⁴ _(q2) of input data matrices 204 ¹, 204 ², 204 ³ and 204 ⁴, respectively. Output element o² ₅ of output data matrix 206 ² is the sum of the dot products of weight set 202 ² and the first block of activation elements within second quadrants a¹ _(q2), a² _(q2), a³ _(q2) and a⁴ _(q2) of input data matrices 204 ¹, 204 ², 204 ³ and 204 ⁴, respectively. Output element o³ ₅ of output data matrix 206 ³ is the sum of the dot products of weight set 202 ³ and the first block of activation elements within second quadrants a¹ _(q2), a² _(q2), a³ _(q2) and a⁴ _(q2) of input data matrices 204 ¹, 204 ², 204 ³ and 204 ⁴, respectively. And, output element o⁴ ₅ of output data matrix 206 ⁴ is the sum of the dot products of weight set 202 ⁴ and the first block of activation elements within second quadrants a¹ _(q2), a² _(q2), a³ _(q2) and a⁴ _(q2) of input data matrices 204 ¹, 204 ², 204 ³ and 204 ⁴, respectively. And so on for output elements o¹ ₆, o¹ ₇ and o¹ ₈, o² ₆, o² ₇ and o² ₈, o³ ₆, o³ ₇ and o³ ₈, and o⁴ ₆, o⁴ ₇ and o⁴ ₈ of the second rows of output data matrices 206 ¹, 206 ², 206 ³ and 206 ⁴.

With respect to quadrant o_(q3), output element o¹ ₉ of output data matrix 206 ¹ is the sum of the dot products of weight set 202 ¹ and the first block of activation elements within third quadrants a¹ _(q3), a² _(q3), a³ _(q3) and a⁴ _(q3) of input data matrices 204 ¹, 204 ², 204 ³ and 204 ⁴, respectively. Output element o² ₉ of output data matrix 206 ² is the sum of the dot products of weight set 202 ² and the first block of activation elements within third quadrants a¹ _(q3), a² _(q3), a³ _(q3) and a⁴ _(q3) of input data matrices 204 ¹, 204 ², 204 ³ and 204 ⁴, respectively. Output element o³ ₉ of output data matrix 206 ³ is the sum of the dot products of weight set 202 ³ and the first block of activation elements within third quadrants a¹ _(q3), a² _(q3), a³ _(q3) and a⁴ _(q3) of input data matrices 204 ¹, 204 ², 204 ³ and 204 ⁴, respectively. And, output element o⁴ ₉ of output data matrix 206 ⁴ is the sum of the dot products of weight set 202 ⁴ and the first block of activation elements within third quadrants a¹ _(q3), a² _(q3), a³ _(q3) and a⁴ _(q3) of input data matrices 204 ¹, 204 ², 204 ³ and 204 ⁴, respectively. And so on for output elements o¹ ₁₀, o¹ ₁₁ and o¹ ₁₂, o² ₁₁₀, o² ₁₁ and o² ₁₂, o³ ₁₀, o³ ₁₁ and o³ ₁₂, and o⁴ ₁₀, o⁴ ₁₁ and o⁴ ₁₂ of the third rows of output data matrices 206 ¹, 206 ², 206 ³ and 206 ⁴.

With respect to quadrant o_(q4), output element o¹ ₁₃ of output data matrix 206 ¹ is the sum of the dot products of weight set 202 ¹ and the first block of activation elements within fourth quadrants a¹ _(q4), a² _(q4), a³ _(q4) and a⁴ _(q4) of input data matrices 204 ¹, 204 ², 204 ³ and 204 ⁴, respectively. Output element o² ₁₃ of output data matrix 206 ² is the sum of the dot products of weight set 202 ² and the first block of activation elements within fourth quadrants a¹ _(q4), a² _(q4), a³ _(q4) and a⁴ _(q4) of input data matrices 204 ¹, 204 ², 204 ³ and 204 ⁴, respectively. Output element o³ ₁₃ of output data matrix 206 ³ is the sum of the dot products of weight set 202 ³ and the first block of activation elements within fourth quadrants a¹ _(q4), a² _(q4), a³ _(q4) and a⁴ _(q4) of input data matrices 204 ¹, 204 ², 204 ³ and 204 ⁴, respectively. And, output element o⁴ ₁₃ of output data matrix 206 ⁴ is the sum of the dot products of weight set 202 ⁴ and the first block of activation elements within third quadrants a¹ _(q4), a² _(q4), a³ _(q4) and a⁴ _(q4) of input data matrices 204 ¹, 204 ², 204 ³ and 204 ⁴, respectively. And so on for output elements o¹ ₁₄, o¹ ₁₅ and o¹ ₁₆, o² ₁₄, o² ₁₅ and o² ₁₆, o³ ₁₄, o³ ₁₅ and o³ ₁₆, and o⁴ ₁₄, o⁴ ₁₅ and o⁴ ₁₆ of the fourth rows of output data matrices 206 ¹, 206 ², 206 ³ and 206 ⁴.

FIG. 3B depicts converted convolutional layer calculation 210 for a CNN, while FIG. 3C depicts converted input data matrix 214, in accordance with an embodiment of the present disclosure.

In one embodiment, the convolutional layer calculations for CNNs may be converted into generic matrix multiplication (GEMM) operations for processing by one or more MMAs. Convolution layer calculation 200 is converted into a GEMM operation by converting filters 202 into converted weight matrix 212, converting input feature maps 204 into converted input data matrix 214, and then multiplying converted weight matrix 212 and converted input data matrix 214 to generate converted output data matrix 216. Because simple matrix multiplication is performed rather than a convolution operation, each output element within converted output data matrix 216 is the dot product of one row of converted weight matrix 212 and one column of converted input data matrix 214. Converted output data matrix 216 is then reformed into output feature maps 206.

Converted weight matrix 212 is a 4×16 matrix, and includes converted weight sets 212 ¹, 212 ², 212 ³ and 212 ⁴. Weight set 202 ¹ is flattened to form converted weight set 212 ¹, i.e., the first row, and includes weights w¹ ₁, w¹ ₂, w¹ ₃, w¹ ₄, w¹ ₅, w¹ ₆, w¹ ₇, w¹ ₈, w¹ ₉, w¹ ₁₀, w¹ ₁₁, w¹ ₁₂, w¹ ₁₃, w¹ ₁₄, w¹ ₁₅ and w¹ ₁₆. Weight set 202 ² is flattened to form converted weight set 212 ², i.e., the second row, and includes weights w² ₁, w² ₂, w² ₃, w² ₄, w² ₅, w² ₆, w² ₇, w² ₈, w² ₉, w² ₁₀, w² ₁₁, w² ₁₂, w² ₁₃, w² ₁₄, w² ₁₅ and w² ₁₆. Weight set 202 ³ is flattened to form converted weight set 212 ³, i.e., the third row, and includes weights w³ ₁, w³ ₂, w³ ₃, w³ ₄, w³ ₅, w³ ₆, w³ ₇, w³ ₈, w³ ₉, w³ ₁₀, w³ ₁₁, w³ ₁₂, w³ ₁₃, w³ ₁₄, w³ ₁₅ and w³ ₁₆. And, weight set 202 ⁴ is flattened to form converted weight set 212 ⁴, i.e., the fourth row, and includes weights w⁴ ₁, w⁴ ₂, w⁴ ₃, w⁴ ₄, w⁴ ₆, w⁴ ₆, w⁴ ₇, w⁴ ₈, w⁴ ₉, w⁴ ₁₀, w⁴ ₁₁, w⁴ ₁₂, w⁴ ₁₃, w⁴ ₁₄, w⁴ ₁₅ and w⁴ ₁₆.

Converted input data matrix 214 is a 16×16 matrix, and includes the blocks of each quadrant of input data matrices 204 ¹, 204 ², 204 ³ and 204 ⁴, i.e., quadrants a¹ _(q1), a¹ _(q2), a¹ _(q3), a¹ _(q4), a² _(q1), a² _(q2), a² _(q3), a² _(q4), a³ _(q1), a³ _(q2), a³ _(q3), a³ _(q4), a⁴ _(q1), a⁴ _(q2), a⁴ _(q3) and a⁴ _(q4), respectively. Generally, each block is flattened to form a portion of a single column of converted input data matrix 214.

More particularly, the first column of converted input matrix 214 includes the first blocks from quadrants a¹ _(q1), a² _(q1), a³ _(q1) and a⁴ _(q1), i.e., activations a¹ ₁, a¹ ₂, a¹ ₆, a¹ ₇, a² ₁, a² ₂, a² ₆, a² ₇, a³ ₁, a³ ₂, a³ ₆, a³ ₇, a⁴ ₁, a⁴ ₂, a⁴ ₆, and a⁴ ₇. The second column of converted input matrix 214 includes the second blocks from quadrants a¹ _(q1), a² _(q1), a³ _(q1) and a⁴ _(q1), i.e., activations a¹ ₂, a¹ ₃, a¹ ₇, a¹ ₈, a² ₂, a² ₃, a² ₇, a² ₈, a³ ₂, a³ ₃, a³ ₇, a³ ₈, a⁴ ₂, a⁴ ₃, a⁴ ₇, and a⁴ ₈. The third column of converted input matrix 214 includes the third blocks from quadrants a¹ _(q1), a² _(q1), a³ _(q1) and a⁴ _(q1), i.e., activations a¹ ₃, a¹ ₄, a¹ ₈, a¹ ₉, a² ₃, a² ₄, a² ₈, a² ₉, a³ ₃, a³ ₄, a³ ₈, a³ ₉, a⁴ ₃, a⁴ ₄, A, and a⁴ ₉. And, the fourth column of converted input matrix 214 includes the fourth blocks from quadrants a¹ _(q1), a² _(q1), a³ _(q1) and a⁴ _(q1), i.e., activations a¹ ₄, a¹ ₅, a¹ ₉, a¹ ₁₀, a² ₄, a² ₅, a² ₉, a² ₁₀, a³ ₄, a³ ₅, a³ ₉, a³ ₁₀, a⁴ ₄, a⁴ ₅, a⁴ ₉, and a⁴ ₁₀.

The remaining columns of converted input data matrix 214 are formed in a similar manner. The fourth to the eighth columns are formed from the blocks of quadrants a¹ _(q2), a² _(q2), a³ _(q2) and a⁴ _(q2), the ninth to the twelfth columns are formed from the blocks of quadrants a¹ _(q3), a² _(q3), a³ _(q3) and a⁴ _(q3), and the thirteenth to the sixteenth columns are formed from the blocks of quadrants a¹ _(q4), a² _(q4), a³ _(q4) and a⁴ _(q4).

Converted output data matrix 216 is a 4×16 matrix, and includes flattened versions of output data matrices 206 ¹, 206 ², 206 ³ and 206 ⁴, i.e., converted output data matrices 216 ¹, 216 ², 216 ³ and 216 ⁴. Converted output data matrix 216 may also be arranged into four quadrants o_(q1), o_(q2), o_(q3) and o_(q4), which include the same output elements as the four quadrants o_(q1), o_(q2), o_(q3) and o_(q4) of output feature maps 206.

The calculation of the output elements in the first row of quadrant o_(q1) of converted output data matrix 216 follows.

Output element oil is the dot product of the first row of converted weight matrix 212, i.e., converted weight set 212 ¹, and the first column of converted input data matrix 214. More particularly, output element oil is equal to w¹ ₁·a¹ ₁+w¹ ₂·a¹ ₂+w¹ ₃+a¹ ₆+w¹ ₄·a¹ ₇+w¹ ₅·a² ₁+w¹ ₆·a² ₂+w¹ ₇·a² ₆+w¹ ₈·a² ₇+w¹ ₉·a³ ₁+w¹ ₁₀·a³ ₂+w¹ ₁₁·a³ ₆+w¹ ₁₂·a³ ₇+w¹ ₁₃·a⁴ ₁+w¹ ₁₄·a⁴ ₂+w¹ ₁₅·a⁴ ₆+w¹ ₁₆·a⁴ ₇. As shown above, output element o₁ ¹ of converted output data matrix 216 is equal to output element oil of output feature maps 206.

Output element o¹ ₂ is the dot product of the first row of converted weight matrix 212, i.e., converted weight set 212 ¹, and the second column of converted input data matrix 214. More particularly, output element o¹ ₂ is equal to w¹ ₁·a¹ ₂+w¹ ₂·a¹ ₃+w¹ ₃·a¹ ₇+w¹ ₄·a¹ ₈+w¹ ₅·a² ₂+w¹ ₆·a² ₃+w¹ ₇·a² ₇+w¹ ₈·a² ₈+w¹ ₉·a³ ₂+w¹ ₁₀·a³ ₃+w¹ ₁₁·a³ ₇+w¹ ₁₂·a³ ₈+w¹ ₁₃·a⁴ ₂+w¹ ₁₄·a⁴ ₃+w¹ ₁₅·a⁴ ₇+w¹ ₁₆·a⁴ ₈. As shown above, output element o¹ ₂ of converted output data matrix 216 is equal to output element o¹ ₂ of output feature maps 206.

Output element o¹ ₃ is the dot product of the first row of converted weight matrix 212, i.e., converted weight set 212 ¹, and the third column of converted input data matrix 214. More particularly, output element o¹ ₃ is equal to w¹ ₁·a¹ ₃+w¹ ₂·a¹ ₄+w¹ ₃·a¹ ₈+w¹ ₄·a¹ ₉+w¹ ₅·a² ₃+w¹ ₆·a² ₄+w¹ ₇·a² ₈+w¹ ₈·a² ₉+w¹ ₉·a³ ₃+w¹ ₁₀·a³ ₄+w¹ ₁₁·a³ ₈+w¹ ₁₂·a³ ₉+w¹ ₁₃·a⁴ ₃+w¹ ₁₄·a⁴ ₄+w¹ ₁₅·a⁴ ₈+w¹ ₁₆·a⁴ ₉. As shown above, output element o¹ ₃ of converted output data matrix 216 is equal to output element o¹ ₃ of output feature maps 206.

Output element o¹ ₄ is the dot product of the first row of converted weight matrix 212, i.e., converted weight set 212 ¹, and the fourth column of converted input data matrix 214. More particularly, output element o¹ ₄ is equal to w¹ ₁·a¹ ₄+w¹ ₂·a¹ ₅+w¹ ₃·a¹ ₉+w¹ ₄·¹ ₁₀+w¹ ₅·a² ₄+w¹ ₆·a² ₅+w¹ ₇·a² ₉+w¹ ₈·a² ₁₀+w¹ ₉·a³ ₄+w¹ ₁₀·a³ ₅+w¹ ₁₁·a³ ₉+w¹ ₁₂·a³ ₁₀+w¹ ₁₃·a⁴ ₄+w¹ ₁₄·a⁴ ₅+w¹ ₁₅·a⁴ ₉+w¹ ₁₆·a⁴ ₁₀. As shown above, output element o¹ ₄ of converted output data matrix 216 is equal to output element o¹ ₄ of output feature maps 206.

For the second row of quadrant ow, output element o² ₁ is the dot product of the second row of converted weight matrix 212, i.e., converted weight set 212 ², and the first column of converted input data matrix 214, output element o² ₂ is the dot product of the second row of converted weight matrix 212, i.e., converted weight set 212 ², and the second column of converted input data matrix 214, output element o² ₃ is the dot product of the second row of converted weight matrix 212, i.e., converted weight set 212 ², and the third column of converted input data matrix 214, and output element o² ₄ is the dot product of the second row of converted weight matrix 212, i.e., converted weight set 212 ², and the fourth column of converted input data matrix 214.

For the third row of quadrant ow, output element o³ ₁ is the dot product of the third row of converted weight matrix 212, i.e., converted weight set 212 ³, and the first column of converted input data matrix 214, output element o³ ₂ is the dot product of the third row of converted weight matrix 212, i.e., converted weight set 212 ³, and the second column of converted input data matrix 214, output element o³ ₃ is the dot product of the third row of converted weight matrix 212, i.e., converted weight set 212 ³, and the third column of converted input data matrix 214, and output element o³ ₄ is the dot product of the third row of converted weight matrix 212, i.e., converted weight set 212 ³, and the fourth column of converted input data matrix 214.

For the fourth row of quadrant o_(q1), output element o⁴ ₁ is the dot product of the fourth row of converted weight matrix 212, i.e., converted weight set 212 ⁴, and the first column of converted input data matrix 214, output element o⁴ ₂ is the dot product of the fourth row of converted weight matrix 212, i.e., converted weight set 212 ⁴, and the second column of converted input data matrix 214, output element o⁴ ₃ is the dot product of the fourth row of converted weight matrix 212, i.e., converted weight set 212 ⁴, and the third column of converted input data matrix 214, and output element o⁴ ₄ is the dot product of the fourth row of converted weight matrix 212, i.e., converted weight set 212 ⁴, and the fourth column of converted input data matrix 214.

The elements of the quadrants o_(q2), o_(q3) and o_(q4) are calculated in a similar manner.

FIG. 4 depicts data flow diagram 220 for MAC array 218.

As noted above, GEMM operations may be implemented in one or more MMAs, which are dedicated ANN hardware accelerators that include one or more arrays of MAC units. In this embodiment, MAC array 218 is a systolic, output stationary array that implements converted convolution operation 210 using a 4×4 array of MAC units m₁, m₂, m₃, m₄, m₅, m₆, m₇, m₈, m₉, m₁₀, m₁₁, m₁₂, m₁₃, m₁₄, m₁₅ and m₁₆. The orientation of transposed converted weight matrix 222, transposed converted input data matrix 224, and transposed converted output data matrix 226 relative to MAC array 218 simplifies illustration; other orientations are also contemplated.

Each MAC unit calculates a dot product, between a row of converted weight matrix 212 and a column of converted input data matrix 214, to generate an element of converted output data matrix 216. Generally, a MAC unit includes, inter alia, a multiplier, an adder and a storage register. Each MAC unit is reset by clearing or zeroing its storage register prior to, or at the start of, a new dot product calculation.

Generally, the rows from converted weight matrix 212 are read from local memory, enter MAC array 218 at the first row of MAC units m₁, m₂, m₃ and m₄, and propagate one MAC unit down at the beginning of each processing cycle. Similarly, the columns from converted input data matrix 214 are read from local memory, enter MAC array 218 at the first column of MAC units m₁, m₅, m₉ and m₁₃, and propagate one MAC unit to the right at the beginning of each processing cycle.

The dot product calculations performed by MAC unit m₁ for the blocks of the first quadrants a¹ _(q1), a² _(q1), a³ _(q1) and a⁴ _(q1) of converted input data matrix 214 are discussed in detail below, while the dot product calculations performed by the remaining MAC units of MAC array 218 are summarized below.

MAC unit m₁ calculates the dot product of the first row of converted weight matrix 212 (i.e., converted weight set 212 ¹) and the first column of converted input data matrix 214 to generate element oil of converted output data matrix 216. During the processing cycle 1, MAC unit m₁ receives a₁ and w¹ ₁ from local memory, multiplies a¹ and w¹ ₁ to generate an intermediate product, adds the intermediate product to the value stored in the storage register (i.e., 0), and stores the accumulated result back in the storage register. During processing cycle 2, MAC unit m₁ transmits a₁ to MAC unit m₂ and w¹ ₁ to MAC unit m₅, receives a₂ and w¹ ₂ from local memory, multiplies a₂ and w¹ ₂ to generate an intermediate product, adds the intermediate product to the value stored in the storage register, and stores the accumulated result back in the storage register.

During processing cycle 3, MAC unit m₁ transmits a₂ to MAC unit m₂ and w¹ ₂ to MAC unit m₅, receives as and w¹ ₃ from local memory, multiplies as and w¹ ₃ to generate an intermediate product, adds the intermediate product to the value stored in the storage register, and stores the accumulated result back in the storage register. During processing cycle 4, MAC unit m₁ transmits as to MAC unit m₂ and w¹ ₃ to MAC unit m₅, receives a₇ and w¹ ₄ from the local memory, multiplies a₇ and w¹ ₄ to generate an intermediate product, adds the intermediate product to the value stored in the storage register, and stores the accumulated result back in the storage register.

Processing cycles 5 through 16 multiply and accumulate the remaining 12 elements of the first row of converted weight matrix 212 and the first column of converted input data matrix 214. At the end of the processing cycle 16, MAC unit m₁ outputs element o¹ ₁.

The remainder of the first row of MAC array 218 includes MAC units m₂, m₃ and m₄.

After an initial delay of one processing cycle, MAC unit m₂ receives weights from the first delay register ff₁ and input data from MAC unit m₁, transmits weights to MAC unit m₆ and input data to MAC unit m₃, and calculates the dot product of the second row of converted weight matrix 212 (i.e., converted weight set 212 ²) and the first column of converted input data matrix 214 to generate element o² ₁ of converted output data matrix 216. The initial delay of one processing cycle allows the delay pipeline (i.e., delay register ff₁) to be filled with weights transferred from memory, and the input data to become available from MAC unit m₁. At the end of the processing cycle 17, MAC unit m₂ outputs element o² ₁.

After an initial delay of two processing cycles, MAC unit m₃ receives weights from the second delay register ff₂ and input data from MAC unit m₂, transmits weights to MAC unit m₇ and input data to MAC unit m₄, and calculates the dot product of the third row of converted weight matrix 212 (i.e., converted weight set 212 ³) and the first column of converted input data matrix 214 to generate element o³ ₁ of converted output data matrix 216. The initial delay of two processing cycles allows the delay pipeline (i.e., delay registers ff₁ and ff₂) to be filled with weights transferred from memory, and the input data to become available from MAC unit m₂. At the end of processing cycle 18, MAC unit m₃ outputs element o³ ₁.

After an initial delay of three processing cycles, MAC unit m₄ receives weights from the third delay register ff₃ and input data from MAC unit m₃, transmits weights to MAC unit m₈, and calculates the dot product of the fourth row of converted weight matrix 212 (i.e., converted weight set 212 ⁴) and the first column of converted input data matrix 214 to generate element o⁴ ₁ of converted output data matrix 216. The initial delay of three processing cycles allows the delay pipeline (i.e., delay registers ff₁, ff₂ and ff₃) to be filled with weights transferred from memory, and the input data to become available from MAC unit m₃. At the end of processing cycle 19, MAC unit m₄ outputs element o⁴ ₁.

The second row of MAC array 218 includes MAC units m₅, m₆, m₇ and m₈.

After an initial delay of one processing cycle, MAC unit m₅ receives weights from MAC unit m₁ and input data from a first delay register ff₁, transmits weights to MAC unit m₉ and input data to MAC unit m₆, and calculates the dot product of the first row of converted weight matrix 212 (i.e., converted weight set 212 ¹) and the second column of converted input data matrix 214 to generate element o¹ ₂ of converted output data matrix 216. The initial delay of one processing cycle allows the delay pipeline (i.e., delay register ff₁) to be filled with input data transferred from memory, and the weights to become available from MAC unit m₁. At the end of processing cycle 17, MAC unit m₅ outputs element o¹ ₂.

After an initial delay of two processing cycles, MAC unit m₆ receives weights from MAC unit m₂ and input data from MAC unit m₅, transmits weights to MAC unit m₁₀ and input data to MAC unit m₇, and calculates the dot product of the second row of converted weight matrix 212 (i.e., converted weight set 212 ²) and the second column of converted input data matrix 214 to generate element o² ₂ of converted output data matrix 216. The initial delay of two processing cycles allows the weights to become available from MAC unit m₂, and the input data to become available from MAC unit m₅. At the end of processing cycle 18, MAC unit m₆ outputs element o² ₂.

After an initial delay of three processing cycles, MAC unit m₇ receives weights from MAC unit m₃ and input data from MAC unit m₆, transmits weights to MAC unit m₁₁ and input data to MAC unit m₈, and calculates the dot product of the third row of converted weight matrix 212 (i.e., converted weight set 212 ³) and the second column of converted input data matrix 214 to generate element o³ ₂ of converted output data matrix 216. The initial delay of three processing cycles allows the weights to become available from MAC unit m₃, and the input data to become available from MAC unit m₆. At the end of processing cycle 19, MAC unit m₇ outputs element o³ ₂.

After an initial delay of four processing cycles, MAC unit m₈ receives weights from MAC unit m₄ and input data from MAC unit m₇, transmits weights to MAC unit m₁₂, and calculates the dot product of the fourth row of converted weight matrix 212 (i.e., converted weight set 212 ⁴) and the second column of converted input data matrix 214 to generate element o⁴ ₂ of converted output data matrix 216. The initial delay of four processing cycles allows the weights to become available from MAC unit m₄, and the input data to become available from MAC unit m₇. At the end of processing cycle 20, MAC unit m₈ outputs element o⁴ ₂.

The third row of MAC array 218 includes MAC units m₉, m₁₀, m₁₁ and m₁₂.

After an initial delay of two processing cycles, MAC unit m₉ receives weights from MAC unit m₅ and input data from a second delay register ff₂, transmits weights to MAC unit m₁₃ and input data to MAC unit m₁₀, and calculates the dot product of the first row of converted weight matrix 212 (i.e., converted weight set 212 ¹) and the third column of converted input data matrix 214 to generate element o¹ ₃ of converted output data matrix 216. The initial delay of two processing cycles allows the delay pipeline (i.e., delay registers ff₁ and ff₂) to be filled with input data transferred from memory, and the weights to become available from MAC unit m₅. At the end of processing cycle 18, MAC unit m₉ outputs element o¹ ₃.

After an initial delay of three processing cycles, MAC unit m₁₀ receives weights from MAC unit m₆ and input data from MAC unit m₉, transmits weights to MAC unit m₁₄ and input data to MAC unit m₁₁, and calculates the dot product of the second row of converted weight matrix 212 (i.e., converted weight set 212 ²) and the third column of converted input data matrix 214 to generate element o² ₃ of converted output data matrix 216. The initial delay of three processing cycles allows the weights to become available from MAC unit m₆, and the input data to become available from MAC unit m₉. At the end of processing cycle 19, MAC unit m₁₀ outputs element o² ₃.

After an initial delay of four processing cycles, MAC unit m₁₁ receives weights from MAC unit m₇ and input data from MAC unit m₁₀, transmits weights to MAC unit m₁₅ and input data to MAC unit m₁₂, and calculates the dot product of the third row of converted weight matrix 212 (i.e., converted weight set 212 ³) and the third column of converted input data matrix 214 to generate element o³ ₃ of converted output data matrix 216. The initial delay of four processing cycles allows the weights to become available from MAC unit m₇, and the input data to become available from MAC unit m₁₀. At the end of processing cycle 20, MAC unit m₁₁ outputs element o³ ₃.

After an initial delay of five processing cycles, MAC unit m₁₂ receives weights from MAC unit m₈ and input data from MAC unit m₁₁, transmits weights to MAC unit m₁₆, and calculates the dot product of the fourth row of converted weight matrix 212 (i.e., converted weight set 212 ⁴) and the third column of converted input data matrix 214 to generate element o⁴ ₃ of converted output data matrix 216. The initial delay of five processing cycles allows the weights to become available from MAC unit m₈, and the input data to become available from MAC unit m₁₁. At the end of processing cycle 21, MAC unit m₁₂ outputs element o⁴ ₃.

The fourth row of MAC array 218 includes MAC units m₁₃, m₁₄, m₁₅ and m₁₆.

After an initial delay of three processing cycles, MAC unit m₁₃ receives weights from MAC unit m₉ and input data from a third delay register ff₃, transmits input data to MAC unit m₁₄, and calculates the dot product of the first row of converted weight matrix 212 (i.e., converted weight set 212 ¹) and the fourth column of converted input data matrix 214 to generate element o¹ ₄ of converted output data matrix 216. The initial delay of three processing cycles allows the delay pipeline (i.e., delay registers ff₁, ff₂ and ff₃) to be filled with input data transferred from memory, and the weights to become available from MAC unit m₉. At the end of processing cycle 19, MAC unit m₁₃ outputs element o¹ ₄.

After an initial delay of four processing cycles, MAC unit m₁₄ receives weights from MAC unit m₁₀ and input data from MAC unit m₁₃, transmits input data to MAC unit m₁₅, and calculates the dot product of the second row of converted weight matrix 212 (i.e., converted weight set 212 ²) and the fourth column of converted input data matrix 214 to generate element o² ₄ of converted output data matrix 216. The initial delay of four processing cycles allows the weights to become available from MAC unit m₁₀, and the input data to become available from MAC unit m₁₃. At the end of processing cycle 20, MAC unit m₁₄ outputs element o² ₄.

After an initial delay of five processing cycles, MAC unit m₁₅ receives weights from MAC unit m₁₁ and input data from MAC unit m₁₄, transmits input data to MAC unit m₁₆, and calculates the dot product of the third row of converted weight matrix 212 (i.e., converted weight set 212 ³) and the fourth column of converted input data matrix 214 to generate element o³ ₄ of converted output data matrix 216. The initial delay of five processing cycles allows the weights to become available from MAC unit mu u, and the input data to become available from MAC unit m₁₄. At the end of processing cycle 21, MAC unit m₁₅ outputs element o³⁴ _(.)

After an initial delay of six processing cycles, MAC unit m₁₆ receives weights from MAC unit m₁₂ and input data from MAC unit m₁₅, and calculates the dot product of the fourth row of converted weight matrix 212 (i.e., converted weight set 212 ⁴) and the fourth column of converted input data matrix 214 to generate element o⁴ ₄ of converted output data matrix 216. The initial delay of six processing cycles allows the weights to become available from MAC unit m₁₂, and the input data to become available from MAC unit m₁₅. At the end of processing cycle 22, MAC unit m₁₆ outputs element o⁴ ₄.

After the blocks of the first quadrants a¹ _(q1), a² _(q1), a³ _(q1) and a⁴ _(q1) of converted input data matrix 214 have been processed, the next sequence of operations processes the blocks of the second quadrants a¹ _(q2), a² _(q2), a³ _(q2) and a⁴ _(q2). After the blocks of the second quadrants a¹ _(q2), a² _(q2), a³ _(q2) and a⁴ _(q2) have been processed, the next sequence of operations processes the blocks of the third quadrants a¹ _(q3), a² _(q3), a³ _(q3) and a⁴ _(q3). And, after the blocks of the third quadrants a¹ _(q3), a² _(q3), a³ _(q3) and a⁴ _(q3) have been processed, the final sequence of operations processes the blocks of the fourth quadrants a¹ _(q4), a² _(q4), a³ _(q4) and a⁴ _(q4). Converted weight matrix 212 is accessed for each sequence of operations.

Many Machine Learning (ML) inference applications employ quantized ANNs, such as quantized CNNs, that require high-throughput, low-precision matrix multiplication operations. A conventional ANN has fixed bit-width dot product datapaths, such as, for example, 8 bits, 16 bits, 32 bits, etc. MMAs that support conventional ANNs include one or more MAC unit arrays that multiply operands having corresponding fixed bit-widths, such as, for example, 8 bits, 16 bits, 32 bits, etc.

A quantized ANN may have smaller bit-width dot product datapaths, such as 3 bits, 4 bits, 5 bits, etc. For example, one matrix for a particular CNN layer may contain weight data having a resolution of 3 bits, while another matrix for this particular CNN layer may contain input data having a resolution of 5 bits. Generally, a quantized ANN may have dot product datapaths with bit-widths that vary from 1 bit to 8 bits (or more), such as, for example, a one-bit dot product (OBDP) datapath, etc.

MMAs that support conventional ANNs may be used to support quantized ANNs.

FIG. 5 depicts the computation of the dot product between vector A 310 and vector B 320 using MAC unit 300, in accordance with an embodiment of the present disclosure.

Vector A 310 includes sixteen 3-bit elements, i.e., A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15 and A16. Vector A 310 may represent, for example, one row from converted weight matrix 212. Vector B 320 includes sixteen 5-bit elements, i.e., B1, B2, B3, B4, B5, B6, B7, B8, B9, B10, B11, B12, B13, B14, B15 and B16. Vector B 320 may represent, for example, one column from converted input data matrix 214. MAC unit 300 calculates the dot product between vector A 310 and vector B 320 by multiplying corresponding pairs of elements as 8-bit unsigned operands (i.e., UINT8), accumulating the intermediate products into a 32-bit accumulator register (ACC), and then outputting 32-bit scalar C 330 (e.g., UINT32, etc.), which may represent, for example, one element from converted output data matrix 216.

More particularly, during the first processing cycle, MAC unit 300 multiplies A1 and B1 as 8-bit operands to generate an intermediate product (i.e., A1 B1), adds the intermediate product to the value stored in the accumulator register (i.e., 0), and then stores the accumulated value back to the accumulator register (i.e., A1 B1). During the second processing cycle, MAC unit 300 multiplies A2 and B2 as 8-bit operands to generate an intermediate product (i.e., A2·B2), adds the intermediate product to the value stored in the accumulator register (i.e., A1·B1) and then stores the accumulated value back to the accumulator register (i.e., A1·B1+A2·B2). MAC unit 300 processes the remaining 14 pairs of elements from vector A 310 and vector B 320 in the same manner, and, after MAC unit 300 has processed A16 and B16, MAC unit 300 outputs the accumulated value stored in the accumulator register as 32-bit scalar C 330 (i.e., A1·B1+A2·B2+A3·B3+A4·B4+A5·B5+A6·B6+A7·B7+A8·B8+A9·B9+A10·B10+A11·B11+A12·B12+A13·B13+A14·B14+A15·B15+A16·B16).

However, using a wide datapath MAC unit array to multiply narrower operands is inefficient because the upper bits of the wide datapath are wasted. For example, a MAC unit that multiplies 3-bit operands and 5-bit operands as 8-bit operands operates much less efficiently that a MAC unit that multiplies 3-bit operands and 5-bit operands at their native resolution. It may be impractical to deploy narrow 1 bit-width to 8 bit-width MAC units in hardware to achieve maximal power and area efficiency.

Embodiments of the present disclosure provide a system and method for efficiently multiplying matrices with variable bit-width operands using an MMA with an array of OBDP units or an array of processors, one or more processors, etc.

FIG. 6A depicts the creation of bitslice vector 410 from vector A 310 depicted in FIG. 5 , in accordance with an embodiment of the present disclosure.

The elements of vector A 310 are first arranged in bit vector form as bit vector A 312. The bit vector for each element of vector A 310 is a sequence of bits from the LSB (i.e., bit position “0”) to the MSB (i.e., bit position “2”). For example, the bit vector for element A1 is {A1 [0], A1 [1], A1 [2]}, where A1 [0] is the value of the bit at the first bit position (i.e., the LSB), A1 [1] is the value of the bit at the second bit position, and A1 [2] is the value of the bit at the third bit position (i.e., the MSB). Similarly, the bit vector for element A2 is {A2[0], A2[1], A2[2]}, where A2[0] is the value of the bit at the first bit position (i.e., the LSB), A2[1] is the value of the bit at the second bit position, and A2[2] is the value of the bit at the third bit position (i.e., the MSB). The remaining elements of bit vector A 312 are formed in a similar manner from the remaining elements of vector A 310. Bit vector A 312 includes 16 bit vectors, i.e., bit vector elements 312 ⁰, . . . , 312 ¹⁵.

Bitslice vector A 410 is formed from bit vector A 312, and includes bit vectors BA[0], BA[1], BA[2], i.e., bitslice vector elements 410 ⁰, 410 ¹, 410 ². Bitslice vector element 410 ⁰ is a sequence of bits formed from the bit at the first bit position of each element of bit vector A 312, i.e., {A1[0], A2[0], A3[0], A4[0], A5[0], A6[0], A7[0], A8[0], A9[0], A10[0], A11[0], A12[0], A13[0], A14[0], A15[0], A16[0]}. Bitslice vector element 410 ¹ is a sequence of bits formed from the bit at the second bit position of each element of bit vector A 312, i.e., {A1 [1], A2[1], A3[1], A4[1], A5[1], A6[1], A7[1], A8[1], A9[1], A10[1], A11[1], A12[1], A13[1], A14[1], A15[1], A16[1]}. Bitslice vector element 410 ² is a sequence of bits formed from the bit at the third bit position of each element of bit vector A 312, i.e., {A1 [2], A2[2], A3[2], A4[2], A5[2], A6[2], A7[2], A8[2], A9[2], A10[2], A11[2], A12[2], A13[2], A14[2], A15[2], A16[2]}.

FIG. 6B depicts the creation of bitslice vector B 420 from vector B 320 depicted in FIG. 5 , in accordance with an embodiment of the present disclosure.

The elements of vector B 320 are first arranged in bit vector form as bit vector B 322. The bit vector for each element of vector B 320 is a sequence of bits from the LSB (i.e., bit position “0”) to the MSB (i.e., bit position “4”). For example, the bit vector for element B1 is {B1[0], B1[1], B1[2], B1[3], B1[4]}, where B1[0] is the value of the bit at the first bit position (i.e., the LSB), B1[1] is the value of the bit at the second bit position, B1[2] is the value of the bit at the third bit position, B1[3] is the value of the bit at the fourth bit position, and B1[4] is the value of the bit at the fifth bit position (i.e., the MSB). Similarly, the bit vector for element B2 is {B2[0], B2[1], B2[2], B2[3], B2[4]}, where B2[0] is the value of the bit at the first bit position (i.e., the LSB), B2[1] is the value of the bit at the second bit position, B2[2] is the value of the bit at the third bit position, B2[3] is the value of the bit at the fourth bit position, and B2[4] is the value of the bit at the fifth bit position (i.e., the MSB). The remaining elements of bit vector B 322 are formed in a similar manner from the remaining elements of vector B 320. Bit vector B 322 includes 16 bit vectors, i.e., bit vector elements 322 ⁰, . . . , 322 ¹⁵.

Bitslice vector B 420 is formed from bit vector B 322, and includes bit vectors BB[0], BB[1], BB[2], BB[3], BB[4], i.e., bitslice vector elements 420 ⁰, 420 ¹, 420 ², 420 ³, 420 ⁴. Bitslice vector element 420 ⁰ is a sequence of bits formed from the bit at the first bit position of each element of bit vector B 312, i.e., {B1[0], B2[0], B3[0], B4[0], B5[0], B6[0], B7[0], B8[0], B9[0], B10[0], B11[0], B12[0], B13[0], B14[0], B15[0], B16[0]}. Bitslice vector element 420 ¹ is a sequence of bits formed from the bit at the second bit position of each element of bit vector B 312, i.e., {B1[1], B2[1], B3[1], B4[1], B5[1], B6[1], B7[1], B8[1], B9[1], B10[1], B11[1], B12[1], B13[1], B14[1], B15[1], B16[1]}. Bitslice vector element 420 ² is a sequence of bits formed from the bit at the third bit position of each element of bit vector B 312, i.e., {B1[2], B2[2], B3[2], B4[2], B5[2], B6[2], B7[2], B8[2], B9[2], B10[2], B11[2], B12[2], B13[2], B14[2], B15[2], B16[2]}. Bitslice vector element 420 ³ is a sequence of bits formed from the bit at the fourth bit position of each element of bit vector B 312, i.e., {B1[3], B2[3], B3[3], B4[3], B5[3], B6[3], B7[3], B8[3], B9[3], B10[3], B11[3], B12[3], B13[3], B14[3], B15[3], B16[3]}. Bitslice vector element 420 ⁴ is a sequence of bits formed from the bit at the fifth bit position of each element of bit vector B 312, i.e., {B1[4], B2[4], B3[4], B4[4], B5[4], B6[4], B7[4], B8[4], B9[4], B10[4], B11[4], B12[4], B13[4], B14[4], B15[4], B16[4]}.

FIG. 6C depicts the computation of the dot product between bitslice vector A 410 and bitslice vector B 420 using one-bit dot product unit 400, in accordance with an embodiment of the present disclosure.

One-bit (or single-bit) dot product unit 400 calculates the dot product between vector A 310 and vector B 320 by multiplying the elements of bitslice vector A 410 and bitslice vector B 420 in a particular sequence, and then outputting 32-bit scalar C 330. Generally, one-bit dot product unit 400 multiplies each bitslice vector element 410 ⁰, 410 ¹ and 410 ² with each bitslice vector element 420 ⁰, 420 ¹, 420 ², 420 ³ and 420 ⁴, accumulates the intermediate products and then generates the 32-bit scalar C 330.

One-bit dot product unit 400 calculates the dot product between any two vectors A and B with the same or different bit-width elements.

In many embodiments, one-bit dot product unit 400 may be implemented as a software process in which the bitslice vector multiplication process is a nested loop in which an outer loop index j selects a particular bitslice vector element 410 (i.e., BA[j]), while an inner loop index k selects a particular bitslice vector element 420 k (i.e., BB[k]). Each iteration of the inner loop multiplies a particular bitslice vector element BA[j] and a particular bitslice vector element BB[k] by performing a bit-wise AND operation and then counting the number of ones that are generated using, for example, a population count function, a sequence of adders including 32 1-bit adders, 50% full adders and 50% half adders, etc. In certain embodiments, the partial reduction may be used for the count.

The nested loop may be given by Equation 1:

$\begin{matrix} {{for}\left( {{{{j = 0};} < 3};{j++}} \right)\left\{ {{for}\left( {{k = 0};{k < 5};{k++}} \right)\left\{ \begin{matrix} {{n = {j + k}};} \\ {{{{int}t} = {{DP}1\left( {{{BA}\lbrack j\rbrack},{{BB}\lbrack k\rbrack}} \right)}};} \\ \left. {\left. {}{{S+={s \cdot \left( {t\operatorname{<<}n} \right)}};} \right\}} \right\} \end{matrix} \right.} \right.} & {{Eq}.1} \end{matrix}$

The function DP1( ) represents the bit-wise AND operation followed by the counting operation, the variable t stores the count value, and the variable S accumulates the values of the intermediate products. Due to the nature of the bit multiplication process, the variable t is left-shifted by the sum of the indices j and k (i.e., n) and then multiplied by a sign parameter, s, prior to accumulation. As described above, indices j and k represent the respective bit positions of the bits in each bitslice. The sign parameter s is either 1 or −1, and, in many embodiments, multiplication by the sign parameter s may be skipped when s is 1.

Generally, while vectors A and B may have elements with the same (or different) bit-widths, vectors A and B are the same type of operand, i.e., unsigned operands or signed operands, such as, for example, unsigned integers (UINT), signed integers (INT), etc. The value for the sign parameter s is based on the values of the indices j and k, and whether the operands are signed or unsigned variables. For unsigned operands, the value of the sign parameter s is 1 for all values of indices j and k. For signed operands, the value of the sign parameter s is −1 for values of indices j and k that represent the most significant bits of the operands, i.e., j=2 and k=4, and 1 for the remaining index values. However, for the last iteration of the loop, e.g., j=2 and k=4 above, the value of the sign parameter s is 1 because both j and k represent the most significant bits of the operands.

Table 1 presents the value of the sign parameter s for the indices j and k for signed vectors A and B.

TABLE 1 Index j Index k s 0 0 1 0 1 1 0 2 1 0 3 1 0 4 −1 1 0 1 1 1 1 1 2 1 1 3 1 1 4 −1 2 0 −1 2 1 −1 2 2 −1 2 3 −1 2 4 1

The functioning of the nested loop is discussed below with respect to 3-bit signed integer vector A and 5-bit signed integer vector B. The value of the sign parameter s is provided by Table 1.

For the first iteration of the nested loop, index j is 0, index k is 0, n is 0 and s is 1. The function DP1( ) first performs the bit-wise AND operation between BA[0] and BB[0] to generate an intermediate bit vector b, as follows:

b = {A1[0]&B1[0], A2[0]&B2[0], A3[0]&B3[0], A4[0]&B4[0], A5[0]&B5[0], A6[0]&B6[0], A7[0]&B7[0], A8[0]&B8[0], A9[0]&B9[0], A10[0]&B10[0], A11[0]&B11[0], A12[0]&B12[0], A13[0]&B13[0], A14[0]&B14[0], A15[0]&B15[0], A16[0]&B16[0]} = {b1, b2, b3, b4, b5, b6, b6, b8, b9, b10, b11, b12, b13, b14, b15, b16}

The function DP1( ) then performs the population count (or POPCOUNT) operation on the intermediate bit vector b to count the number of bits bn that have a value of one. The result is returned and assigned to the variable t, which is left-shifted by 0 bits, multiplied by 1 and then added to the variable S.

For the 2^(nd) iteration of the nested loop, index j is 0, index k is 1, n is 1, and s is 1. The function DP1( ) first performs the bit-wise AND operation between BA[0] and BB[1] to generate the intermediate bit vector b, as follows:

b = {A1[0]&B1[0], A2[0]&B2[0], A3[0]&B3[0], A4[0]&B4[0], A5[0]&B5[0], A6[0]&B6[0], A7[0]&B7[0], A8[0]&B8[0], A9[0]&B9[0], A10[0]&B10[0], A11[0]&B11[0], A12[0]&B12[0], A13[0]&B13[0], A14[0]&B14[0], A15[0]&B15[0], A16[0]&B16[0]} = {b1, b2, b3, b4, b5, b6, b6, b8, b9, b10, b11, b12, b13, b14, b15, b16}

The function DP1( ) then performs the population count operation on the intermediate bit vector b to count the number of bits bn that have a value of one. The result is returned and assigned to the variable t, which is left-shifted by 1 bit, multiplied by 1 and then added to the variable S.

For the 3^(rd) iteration of the nested loop, index j is 0, index k is 2, n is 2, and s is 1. The function DP1( ) first performs the bit-wise AND operation between BA[0] and BB[2] to generate the intermediate bit vector b, as follows:

b = {A1[0]&B1[0], A2[0]&B2[0], A3[0]&B3[0], A4[0]&B4[0], A5[0]&B5[0], A6[0]&B6[0], A7[0]&B7[0], A8[0]&B8[0], A9[0]&B9[0], A10[0]&B10[0], A11[0]&B11[0], A12[0]&B12[0], A13[0]&B13[0], A14[0]&B14[0], A15[0]&B15[0], A16[0]&B16[0]} = {b1, b2, b3, b4, b5, b6, b6, b8, b9, b10, b11, b12, b13, b14, b15, b16}

The function DP1( ) then performs the population count operation on the intermediate bit vector b to count the number of bits bn that have a value of one. The result is returned and assigned to the variable t, which is left-shifted by 2 bits, multiplied by 1 and then added to the variable S.

For the 4^(th) iteration of the nested loop, index j is 0, index k is 3, n is 3, and s is 1. The function DP1( ) first performs the bit-wise AND operation between BA[0] and BB[3] to generate the intermediate bit vector b, as follows:

b = {A1[0]&B1[0], A2[0]&B2[0], A3[0]&B3[0], A4[0]&B4[0], A5[0]&B5[0], A6[0]&B6[0], A7[0]&B7[0], A8[0]&B8[0], A9[0]&B9[0], A10[0]&B10[0], A11[0]&B11[0], A12[0]&B12[0], A13[0]&B13[0], A14[0]&B14[0], A15[0]&B15[0], A16[0]&B16[0]} = {b1, b2, b3, b4, b5, b6, b6, b8, b9, b10, b11, b12, b13, b14, b15, b16}

The function DP1( ) then performs the population count operation on the intermediate bit vector b to count the number of bits bn that have a value of one. The result is returned and assigned to the variable t, which is left-shifted by 3 bits, multiplied by 1 and then added to the variable S.

For the 5^(th) iteration of the nested loop, index j is 0, index k is 4, n is 4, and s is −1. The function DP1( ) first performs the bit-wise AND operation between BA[0] and BB[4] to generate the intermediate bit vector b, as follows:

b = {A1[0]&B1[0], A2[0]&B2[0], A3[0]&B3[0], A4[0]&B4[0], A5[0]&B5[0], A6[0]&B6[0], A7[0]&B7[0], A8[0]&B8[0], A9[0]&B9[0], A10[0]&B10[0], A11[0]&B11[0], A12[0]&B12[0], A13[0]&B13[0], A14[0]&B14[0], A15[0]&B15[0], A16[0]&B16[0]} = {b1, b2, b3, b4, b5, b6, b6, b8, b9, b10, b11, b12, b13, b14, b15, b16}

The function DP1( ) then performs the population count operation on the intermediate bit vector b to count the number of bits bn that have a value of one. The result is returned and assigned to the variable t, which is left-shifted by 4 bits, multiplied by −1 and then added to the variable S.

For the 6^(th) iteration of the nested loop, index j is 1, index k is 0, n is 1, and s is 1. The function DP1( ) first performs the bit-wise AND operation between BA[1] and BB[0] to generate an intermediate bit vector b, as follows:

b = {A1[0]&B1[0], A2[0]&B2[0], A3[0]&B3[0], A4[0]&B4[0], A5[0]&B5[0], A6[0]&B6[0], A7[0]&B7[0], A8[0]&B8[0], A9[0]&B9[0], A10[0]&B10[0], A11[0]&B11[0], A12[0]&B12[0], A13[0]&B13[0], A14[0]&B14[0], A15[0]&B15[0], A16[0]&B16[0]} = {b1, b2, b3, b4, b5, b6, b6, b8, b9, b10, b11, b12, b13, b14, b15, b16}

The function DP1( ) then performs the population count operation on the intermediate bit vector b to count the number of bits bn that have a value of one. The result is returned and assigned to the variable t, which is left-shifted by 1 bit, multiplied by 1 and then added to the variable S.

For the 7^(th) iteration of the nested loop, index j is 1, index k is 1, n is 2, and s is 1. The function DP1( ) first performs the bit-wise AND operation between BA[1] and BB[1] to generate the intermediate bit vector b, as follows:

b = {A1[0]&B1[0], A2[0]&B2[0], A3[0]&B3[0], A4[0]&B4[0], A5[0]&B5[0], A6[0]&B6[0], A7[0]&B7[0], A8[0]&B8[0], A9[0]&B9[0], A10[0]&B10[0], A11[0]&B11[0], A12[0]&B12[0], A13[0]&B13[0], A14[0]&B14[0], A15[0]&B15[0], A16[0]&B16[0]} = {b1, b2, b3, b4, b5, b6, b6, b8, b9, b10, b11, b12, b13, b14, b15, b16}

The function DP1( ) then performs the population count operation on the intermediate bit vector b to count the number of bits bn that have a value of one. The result is returned and assigned to the variable t, which is left-shifted by 2 bits, multiplied by 1 and then added to the variable S.

For the 8^(th) iteration of the nested loop, index j is 1, index k is 2, n is 3, and s is 1. The function DP1( ) first performs the bit-wise AND operation between BA[1] and BB[2] to generate the intermediate bit vector b, as follows:

b = {A1[0]&B1[0], A2[0]&B2[0], A3[0]&B3[0], A4[0]&B4[0], A5[0]&B5[0], A6[0]&B6[0], A7[0]&B7[0], A8[0]&B8[0], A9[0]&B9[0], A10[0]&B10[0], A11[0]&B11[0], A12[0]&B12[0], A13[0]&B13[0], A14[0]&B14[0], A15[0]&B15[0], A16[0]&B16[0]} = {b1, b2, b3, b4, b5, b6, b6, b8, b9, b10, b11, b12, b13, b14, b15, b16}

The function DP1( ) then performs the population count operation on the intermediate bit vector b to count the number of bits bn that have a value of one. The result is returned and assigned to the variable t, which is left-shifted by 3 bits, multiplied by 1 and then added to the variable S.

For the 9^(th) iteration of the nested loop, index j is 1, index k is 3, n is 4, and s is 1. The function DP1( ) first performs the bit-wise AND operation between BA[1] and BB[3] to generate the intermediate bit vector b, as follows:

b = {A1[0]&B1[0], A2[0]&B2[0], A3[0]&B3[0], A4[0]&B4[0], A5[0]&B5[0], A6[0]&B6[0], A7[0]&B7[0], A8[0]&B8[0], A9[0]&B9[0], A10[0]&B10[0], A11[0]&B11[0], A12[0]&B12[0], A13[0]&B13[0], A14[0]&B14[0], A15[0]&B15[0], A16[0]&B16[0]} = {b1, b2, b3, b4, b5, b6, b6, b8, b9, b10, b11, b12, b13, b14, b15, b16}

The function DP1( ) then performs the population count operation on the intermediate bit vector b to count the number of bits bn that have a value of one. The result is returned and assigned to the variable t, which is left-shifted by 4 bits, multiplied by 1 and then added to the variable S.

For the 10^(th) iteration of the nested loop, index j is 1, index k is 4, n is 5, and s is −1. The function DP1( ) first performs the bit-wise AND operation between BA[1] and BB[4] to generate the intermediate bit vector b as follows:

b = {A1[0]&B1[0], A2[0]&B2[0], A3[0]&B3[0], A4[0]&B4[0], A5[0]&B5[0], A6[0]&B6[0], A7[0]&B7[0], A8[0]&B8[0], A9[0]&B9[0], A10[0]&B10[0], A11[0]&B11[0], A12[0]&B12[0], A13[0]&B13[0], A14[0]&B14[0], A15[0]&B15[0], A16[0]&B16[0]} = {b1, b2, b3, b4, b5, b6, b6, b8, b9, b10, b11, b12, b13, b14, b15, b16}

The function DP1( ) then performs the population count operation on the intermediate bit vector b to count the number of bits bn that have a value of one. The result is returned and assigned to the variable t, which is left-shifted by 5 bits, multiplied by −1 and then added to the variable S.

For the 11^(th) iteration of the nested loop, index j is 2, index k is 0, n is 2, and s is −1. The function DP1( ) first performs the bit-wise AND operation between BA[2] and BB[0] to generate an intermediate bit vector b, as follows:

b = {A1[0]&B1[0], A2[0]&B2[0], A3[0]&B3[0], A4[0]&B4[0], A5[0]&B5[0], A6[0]&B6[0], A7[0]&B7[0], A8[0]&B8[0], A9[0]&B9[0], A10[0]&B10[0], A11[0]&B11[0], A12[0]&B12[0], A13[0]&B13[0], A14[0]&B14[0], A15[0]&B15[0], A16[0]&B16[0]} = {b1, b2, b3, b4, b5, b6, b6, b8, b9, b10, b11, b12, b13, b14, b15, b16}

The function DP1( ) then performs the population count operation on the intermediate bit vector b to count the number of bits bn that have a value of one. The result is returned and assigned to the variable t, which is left-shifted by 2 bits, multiplied by −1 and then added to the variable S.

For the 12^(th) iteration of the nested loop, index j is 2, index k is 1, n is 3, and s is −1. The function DP1( ) first performs the bit-wise AND operation between BA[2] and BB[1] to generate the intermediate bit vector b, as follows:

b = {A1[0]&B1[0], A2[0]&B2[0], A3[0]&B3[0], A4[0]&B4[0], A5[0]&B5[0], A6[0]&B6[0], A7[0]&B7[0], A8[0]&B8[0], A9[0]&B9[0], A10[0]&B10[0], A11[0]&B11[0], A12[0]&B12[0], A13[0]&B13[0], A14[0]&B14[0], A15[0]&B15[0], A16[0]&B16[0]} = {b1, b2, b3, b4, b5, b6, b6, b8, b9, b10, b11, b12, b13, b14, b15, b16}

The function DP1( ) then performs the population count operation on the intermediate bit vector b to count the number of bits bn that have a value of one. The result is returned and assigned to the variable t, which is left-shifted by 3 bits, multiplied by −1 and then added to the variable S.

For the 13^(th) iteration of the nested loop, index j is 2, index k is 2, n is 4, and s is −1. The function DP1( ) first performs the bit-wise AND operation between BA[1] and BB[2] to generate the intermediate bit vector b, as follows:

b = {A1[0]&B1[0], A2[0]&B2[0], A3[0]&B3[0], A4[0]&B4[0], A5[0]&B5[0], A6[0]&B6[0], A7[0]&B7[0], A8[0]&B8[0], A9[0]&B9[0], A10[0]&B10[0], A11[0]&B11[0], A12[0]&B12[0], A13[0]&B13[0], A14[0]&B14[0], A15[0]&B15[0], A16[0]&B16[0]} = {b1, b2, b3, b4, b5, b6, b6, b8, b9, b10, b11, b12, b13, b14, b15, b16}

The function DP1( ) then performs the population count operation on the intermediate bit vector b to count the number of bits bn that have a value of one. The result is returned and assigned to the variable t, which is left-shifted by 4 bits, multiplied by −1 and then added to the variable S.

For the 14^(th) iteration of the nested loop, index j is 2, index k is 3, n is 5, and s is −1. The function DP1( ) first performs the bit-wise AND operation between BA[2] and BB[3] to generate the intermediate bit vector b, as follows:

b = {A1[0]&B1[0], A2[0]&B2[0], A3[0]&B3[0], A4[0]&B4[0], A5[0]&B5[0], A6[0]&B6[0], A7[0]&B7[0], A8[0]&B8[0], A9[0]&B9[0], A10[0]&B10[0], A11[0]&B11[0], A12[0]&B12[0], A13[0]&B13[0], A14[0]&B14[0], A15[0]&B15[0], A16[0]&B16[0]} = {b1, b2, b3, b4, b5, b6, b6, b8, b9, b10, b11, b12, b13, b14, b15, b16}

The function DP1( ) then performs the population count operation on the intermediate bit vector b to count the number of bits bn that have a value of one. The result is returned and assigned to the variable t, which is left-shifted by 5 bits, multiplied by −1 and then added to the variable S.

For the 15^(th) and final iteration of the nested loop, index j is 2, index k is 4, n is 6, and s is 1. The function DP1( ) first performs the bit-wise AND operation between BA[2] and BB[4] to generate the intermediate bit vector b, as follows:

b = {A1[0]&B1[0], A2[0]&B2[0], A3[0]&B3[0], A4[0]&B4[0], A5[0]&B5[0], A6[0]&B6[0], A7[0]&B7[0], A8[0]&B8[0], A9[0]&B9[0], A10[0]&B10[0], A11[0]&B11[0], A12[0]&B12[0], A13[0]&B13[0], A14[0]&B14[0], A15[0]&B15[0], A16[0]&B16[0]} = {b1, b2, b3, b4, b5, b6, b6, b8, b9, b10, b11, b12, b13, b14, b15, b16}

The function DP1( ) then performs the population count operation on the intermediate bit vector b to count the number of bits bn that have a value of one. The result is returned and assigned to the variable t, which is left-shifted by 6 bits, multiplied by 1 and then added to the variable S.

After the last loop has completed, one-bit dot product unit 400 outputs the final value of S as 32-bit scalar C 330. For this embodiment, there are a total of 15 loops, and, optionally, a loop iteration may be skipped if either BA[j] or BB[k] has a value of zero in each bit position. While vector A 310 and vector B 320 are 16 element vectors, any vectors with the same number of elements may be accommodated.

FIG. 7A depicts a first example of the computation of the dot product between vector A 310 and vector B 320 using one-bit dot product unit 400, in accordance with an embodiment of the present disclosure.

Vector A 310 includes sixteen 3-bit unsigned integer elements, i.e., A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15 and A16, all of which are equal to 1 (i.e., binary “001”). Vector B 320 includes sixteen 5-bit unsigned integer elements, i.e., B1, B2, B3, B4, B5, B6, B7, B8, B9, B10, B11, B12, B13, B14, B15 and B16, all of which are equal to 1 (i.e., binary “00001”). Bitslice vectors 410 ⁰, 410 ¹ and 410 ² are depicted, as well as bitslice vectors 420 ⁰, 420 ¹, 420 ², 420 ³, and 420 ⁴. Scalar C 330 is equal to 16. Result 332 is the result of the calculation of the decimal dot product, and is also equal to 16. Difference 333 between scalar C 330 and result 332 is equal to 0.

FIG. 7B depicts a second example of the computation of the dot product between vector A 310 and vector B 320 using one-bit dot product unit 400, in accordance with an embodiment of the present disclosure.

Vector A 310 includes sixteen 3-bit unsigned integer elements, i.e., A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15 and A16, all of which are equal to 7 (i.e., binary “111”). Vector B 320 includes sixteen 5-bit unsigned integer elements, i.e., B1, B2, B3, B4, B5, B6, B7, B8, B9, B10, B11, B12, B13, B14, B15 and B16, all of which are equal to 31 (i.e., binary “11111”). Bitslice vectors 410 ⁰, 410 ¹ and 410 ² are depicted, as well as bitslice vectors 420 ⁰, 420 ¹, 420 ², 420 ³, and 420 ⁴. Scalar C 330 is equal to 3,472, result 332 is also equal to 3,472, and difference 333 is equal to 0.

FIG. 7C depicts a third example of the computation of the dot product between vector A 310 and vector B 320 using one-bit dot product unit 400, in accordance with an embodiment of the present disclosure.

Vector A 310 includes sixteen 3-bit unsigned integer elements, i.e., A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15 and A16. A1 is equal to 0 (i.e., binary “000”), A2 is equal to 1 (i.e., binary “001”), A3 is equal to 1 (i.e., binary “001”), A4 is equal to 0 (i.e., binary “000”), A5 is equal to 3 (i.e., binary “011”), A6 is equal to 7 (i.e., binary “111”), A7 is equal to 7 (i.e., binary “111”), A8 is equal to 3 (i.e., binary “011”), A9 is equal to 3 (i.e., binary “011”), A10 is equal to 7 (i.e., binary “111”), A11 is equal to 7 (i.e., binary “111”), A12 is equal to 3 (i.e., binary “011”), A13 is equal to 0 (i.e., binary “000”), A14 is equal to 1 (i.e., binary “001”), A15 is equal to 1 (i.e., binary “001”), and A16 is equal to 0 (i.e., binary “000”).

Vector B 320 includes sixteen 5-bit unsigned integer elements, i.e., B1, B2, B3, B4, B5, B6, B7, B8, B9, B10, B11, B12, B13, B14, B15 and B16. B1 is equal to 1 (i.e., binary “00001”), B2 is equal to 2 (i.e., binary “00010”), B3 is equal to 2 (i.e., binary “00010”), B4 is equal to 1 (i.e., binary “00001”), B5 is equal to 3 (i.e., binary “00011”), B6 is equal to 6 (i.e., binary “00110”), B7 is equal to 6 (i.e., binary “00110”), B8 is equal to 3 (i.e., binary “00011”), B9 is equal to 3 (i.e., binary “00011”), B10 is equal to 9 (i.e., binary “01001”), B11 is equal to 9 (i.e., binary “01001”), B12 is equal to 3 (i.e., binary “00011”), B13 is equal to 1 (i.e., binary “00001”), B14 is equal to 2 (i.e., binary “0010”), B15 is equal to 2 (i.e., binary “00010”), and B16 is equal to 1 (i.e., binary “00001”).

Bitslice vectors 410 ⁰, 410 ¹ and 410 ² are depicted, as well as bitslice vectors 420 ⁰, 420 ¹, 420 ², 420 ³, and 420 ⁴. Scalar C 330 is equal to 254, result 332 is also equal to 254, and difference 333 is equal to 0.

FIG. 7D depicts a fourth example of the computation of the dot product between vector A 310 and vector B 320 using one-bit dot product unit 400, in accordance with an embodiment of the present disclosure.

Vector A 310 includes sixteen 3-bit signed integer elements, i.e., A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15 and A16. Elements A1, A2, A3, A4, A5, A6, A7 and A8 are equal to −1 (i.e., binary “111”), and elements A9, A10, A11, A12, A13, A14, A15 and A16 are equal to 1 (i.e., binary “001”). Vector B 320 includes sixteen 5-bit signed integer elements, i.e., B1, B2, B3, B4, B5, B6, B7, B8, B9, B10, B11, B12, B13, B14, B15 and B16. Elements B1, B2, B3, B4, B5, B6, B7 and B8 are equal to 1 (i.e., binary “00001”), and elements B9, B10, B11, B12, B13, B14, B15 and B16 are equal to −1 (i.e., binary “11111”). Bitslice vectors 410 ⁰, 410 ¹ and 410 ² are depicted, as well as bitslice vectors 420 ⁰, 420 ¹, 420 ², 420 ³, and 420 ⁴. Scalar C 330 is equal to −16, result 332 is also equal to −16, and difference 333 is equal to 0.

FIG. 7E depicts a fifth example of the computation of the dot product between vector A 310 and vector B 320 using one-bit dot product unit 400, in accordance with an embodiment of the present disclosure.

Vector A 310 includes sixteen 3-bit signed integer elements, i.e., A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15 and A16. Elements A1, A2, A3, A4, A5, A6, A7 and A8 are equal to 3 (i.e., binary “011”), and elements A9, A10, A11, A12, A13, A14, A15 and A16 are equal to −4 (i.e., binary “100”). Vector B 320 includes sixteen 5-bit signed integer elements, i.e., B1, B2, B3, B4, B5, B6, B7, B8, B9, B10, B11, B12, B13, B14, B15 and B16. Elements B1, B2, B3, B4, B5, B6, B7 and B8 are equal to −16 (i.e., binary “10000”), and elements B9, B10, B11, B12, B13, B14, B15 and B16 are equal to 15 (i.e., binary “011111”). Bitslice vectors 410 ⁰, 410 ¹ and 410 ² are depicted, as well as bitslice vectors 420 ⁰, 420 ¹, 420 ², 420 ³, and 420 ⁴. Scalar C 330 is equal to −864, result 332 is also equal to −864, and difference 333 is equal to 0.

FIG. 7F depicts a sixth example of the computation of the dot product between vector A 310 and vector B 320 using one-bit dot product unit 400, in accordance with an embodiment of the present disclosure.

Vector A 310 includes sixteen 3-bit signed integer elements, i.e., A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15 and A16. A1 is equal to −4 (i.e., binary “100”), A2 is equal to −3 (i.e., binary “101”), A3 is equal to −2 (i.e., binary “110”), A4 is equal to −1 (i.e., binary “111”), A5 is equal to 0 (i.e., binary “000”), A6 is equal to 1 (i.e., binary “001”), A7 is equal to 2 (i.e., binary “010”), A8 is equal to 3 (i.e., binary “011”), A9 is equal to 3 (i.e., binary “011”), A10 is equal to 2 (i.e., binary “010”), A11 is equal to 1 (i.e., binary “001”), A12 is equal to 0 (i.e., binary “000”), A13 is equal to −1 (i.e., binary “111”), A14 is equal to −2 (i.e., binary “110”), A15 is equal to −3 (i.e., binary “101”), and A16 is equal to −4 (i.e., binary “100”).

Vector B 320 includes sixteen 5-bit signed integer elements, i.e., B1, B2, B3, B4, B5, B6, B7, B8, B9, B10, B11, B12, B13, B14, B15 and B16. B1 is equal to 15 (i.e., binary “01111”), B2 is equal to 13 (i.e., binary “01101”), B3 is equal to 11 (i.e., binary “01011”), B4 is equal to 9 (i.e., binary “01001”), B5 is equal to 7 (i.e., binary “00111”), B6 is equal to 5 (i.e., binary “00101”), B7 is equal to 3 (i.e., binary “00011”), B8 is equal to 1 (i.e., binary “00001”), B9 is equal to −2 (i.e., binary “11110”), B10 is equal to −4 (i.e., binary “11100”), B11 is equal to −6 (i.e., binary “11010”), B12 is equal to −8 (i.e., binary “11000”), B13 is equal to −10 (i.e., binary “10110”), B14 is equal to −12 (i.e., binary “10100”), B15 is equal to −14 (i.e., binary “10010”), and B16 is equal to −16 (i.e., binary “10000”).

Bitslice vectors 410 ⁰, 410 ¹ and 410 ² are depicted, as well as bitslice vectors 420 ⁰, 420 ¹, 420 ², 420 ³, and 420 ⁴. Scalar C 330 is equal to 4, result 332 is also equal to 4, and difference 333 is equal to 0.

In one embodiment, the conversion of vectors A and B to bitslice representation may be performed by a system processor, such as, for example, a central processing unit (CPU), etc. In another embodiment, the conversion of vectors A and B to bitslice representation may be performed by an MMA processor, such as, for example a processor or processor core, microprocessor, controller, microcontroller, etc.

Embodiments of the present disclosure break down variable bit-width vectors to 1-bit operations to increase power efficiency for variable bit-width matrix multiplications. The power reduction for the embodiment described above would be approximately (8·8)/(3·5)=64/15=4.3x.

In another embodiment, a first matrix and a second matrix are multiplied to generate a third matrix. The multiplication of each row of the first matrix with each column of the second matrix is a dot product operation that generates one element of the third matrix.

FIGS. 8A and 8B depict the creation of bitslice tensor X 455 from matrix X 340, in accordance with an embodiment of the present disclosure.

Matrix X 340 and matrix Y 360 are multiplied to generate matrix Z 380. Matrix X 340 is a 4×4 matrix having 16 3-bit elements. The first row includes elements x¹ ₁, x¹ ₂, x¹ ₃ and x¹ ₄, the second row includes elements x² ₁, x² ₂, x² ₃ and x² ₄, the third row includes elements x³ ₁, x³ ₂, x³ ₃ and x³ ₄, and the fourth row includes elements x⁴ ₁, x⁴ ₂, x⁴ ₃ and x⁴ ₄.

Matrix Y 360 is a 4×4 matrix having 16 5-bit elements. The first column includes elements y¹ ₁, y² ₁, y³ ₁ and y⁴ ₁, the second column includes elements y¹ ₂, y² ₂, y³ ₂ and y⁴ ₂, the third column includes elements y¹ ₃, y² ₃, y³ ₃ and y⁴ ₃, and the fourth column includes elements y¹ ₄, y² ₄, y³ ₄ and y⁴ ₄.

Matrix Z 380 is a 4×4 matrix having 16 32-bit elements. The first row includes elements z¹ ₁, z¹ ₂, z¹ ₃ and z¹ ₄, the second row includes elements z² ₁, z² ₂, z² ₃ and z² ₄, the third row includes elements z³ ₁, z³ ₂, z³ ₃ and z³ ₄, and the fourth row includes elements z⁴ ₁, z⁴ ₂, z⁴ ₃ and z⁴ ₄.

Generally, the elements of the rows of matrix X 340 are first arranged in bit vector form. The elements of the first row of matrix X 340 are arranged in bit vector form as bit vector X¹ 341, the elements of the second row of matrix X 340 are arranged in bit vector form as bit vector X² 342, the elements of the third row of matrix X 340 are arranged in bit vector form as bit vector X³ 343, and the elements of the fourth row of matrix X 340 are arranged in bit vector form as bit vector X⁴ 344.

The bit vector for each element of bit vector X¹ 341, bit vector X² 342, bit vector X³ 343 and bit vector X⁴ 344 is a sequence of bits from the LSB (i.e., bit position “0”) to the MSB (i.e., bit position “2”). With respect to bit vector X¹ 341, the bit vector for element x¹ ₁ is {x¹ ₁[0], x¹ ₁[1], x¹ ₁[2]}, where x¹ ₁[0] is the value of the bit at the first bit position (i.e., the LSB), x¹ ₁[1] is the value of the bit at the second bit position, and x¹ ₁[2] is the value of the bit at the third bit position (i.e., the MSB). Similarly, the bit vector for element x¹ ₂ is {x¹ ₂[0], x¹ ₂[1], x¹ ₂[2]}, the bit vector for element x¹ ₃ is {x¹ ₃[0], x¹ ₃[1], x¹ ₃[2] }, and the bit vector for element x¹ ₄ is {x¹ ₄[0], x¹ ₄[1], x¹ ₄[2]}. Bit vector X¹ 341 includes 4 bit vectors, i.e., bit vector elements 341 ⁰, 341 ¹, 341 ², 341 ³.

Bit vector X² 342, bit vector X³ 343, and bit vector X⁴ 344 are formed in a similar manner from the second, third and fourth rows of matrix X 340, respectively. Bit vector X² 342 includes 4 bit vectors, i.e., bit vector elements 342 ⁰, 342 ¹, 342 ², 342 ³. Bit vector X³ 343 includes 4 bit vectors, i.e., bit vector elements 343 ⁰, 343 ¹, 343 ², 343 ³. Bit vector X⁴ 344 includes 4 bit vectors, i.e., bit vector elements 344 ⁰, 344 ¹, 344 ², 344 ³.

Bitslice vector set 440 includes bitslice vector BX¹ 441, bitslice vector BX² 442, bitslice vector BX³ 443 and bitslice vector BX⁴ 444.

Bitslice vector BX¹ 441 is formed from bit vector X¹ 341, and includes bit vectors BX¹[0], BX¹[1], BX¹[2], i.e., bitslice vector elements 441 ⁰, 441 ¹, 441 ², respectively. Bitslice vector element 441 ⁰ is a sequence of bits formed from the bit at the first bit position of each element of bit vector X¹ 341, i.e., {x¹ ₁[0], x¹ ₂[0], x¹ ₃[0], x¹ ₄[0]}, bitslice vector element 441 ¹ is a sequence of bits formed from the bit at the second bit position of each element of bit vector X¹ 341, i.e., {x¹ ₁[1], x¹ ₂[1], x¹ ₃[1], x¹ ₄[1]}. Bitslice vector element 441 ² is a sequence of bits formed from the bit at the third bit position of each element of bit vector X¹ 341, i.e., {x¹ ₁[2], x¹ ₂[2], x¹ ₃[2], x¹ ₄[2]}.

Bitslice vector BX² 442, bitslice vector BX³ 443 and bitslice vector BX⁴ 444 are formed in a similar manner from bit vector X² 342, bit vector X³ 343 and bit vector X⁴ 344, respectively. Bitslice vector BX² 442 includes bit vectors BX²[0], BX²[1], BX²[2], i.e., bitslice vector elements 442 ⁰, 442 ¹, 442 ². Bitslice vector BX³ 442 includes bit vectors BX³[0], BX³[1], BX³[2], i.e., bitslice vector elements 443 ⁰, 443 ¹, 443 ². Bitslice vector BX⁴ 442 includes bit vectors BX⁴[0], BX⁴[1], BX⁴[2], i.e., bitslice vector elements 444 ⁰, 444 ¹, 444 ².

Bitslice vector set 450 includes bitslice vector BX¹ 451, bitslice vector BX² 452, bitslice vector BX³ 453 and bitslice vector BX⁴ 454. Bitslice vector BX¹ 451 is formed from bitslice vector BX¹ 441 and includes bitslice vector elements 441 ⁰, 441 ¹, 441 ². Bitslice vector BX² 452 is formed from bitslice vector BX² 442 and includes bitslice vector elements 442 ⁰, 442 ¹, 442 ². Bitslice vector BX³ 453 is formed from bitslice vector BX³ 443 and includes bitslice vector elements 443 ⁰, 443 ¹, 443 ². Bitslice vector BX⁴ 454 is formed from bitslice vector BX⁴ 444 and includes bitslice vector elements 444 ⁰, 444 ¹, 444 ².

Bitslice tensor X 455 is formed from bitslice vector BX¹ 451, bitslice vector BX² 452, bitslice vector BX³ 453 and bitslice vector BX⁴ 454.

FIGS. 8C and 8D depict the creation of bitslice tensor Y 475 from matrix Y 360, in accordance with an embodiment of the present disclosure.

Generally, the elements of the columns of matrix Y 360 are first arranged in bit vector form. The elements of the first column of matrix Y 360 are arranged in bit vector form as bit vector Y¹ 361, the elements of the second column of matrix Y 360 are arranged in bit vector form as bit vector Y² 362, the elements of the third column of matrix Y 360 are arranged in bit vector form as bit vector Y³ 363, and the elements of the fourth column of matrix Y 360 are arranged in bit vector form as bit vector Y⁴ 364.

The bit vector for each element of bit vector Y¹ 361, bit vector Y² 362, bit vector Y³ 363 and bit vector Y⁴ 364 is a sequence of bits from the LSB (i.e., bit position “0”) to the MSB (i.e., bit position “4”). With respect to bit vector Y¹ 361, the bit vector for element y¹ ₁ is {y¹ ₁[0], y¹ ₁[1], y¹ ₁[2], y¹ ₁[3], y¹ ₁[4]}, where y¹ ₁[0] is the value of the bit at the first bit position (i.e., the LSB), y¹ ₁[1] is the value of the bit at the second bit position, y¹ ₁[2] is the value of the bit at the third bit position, y¹ ₁[3] is the value of the bit at the fourth bit position, and y¹ ₁[4] is the value of the bit at the fifth bit position (i.e., the MSB). Similarly, the bit vector for element y² ₁ is {y² ₁[0], y² ₁[1], y² ₁[2], y² ₁[3], y² ₁[4]}, the bit vector for element y³ ₁ is {y³ ₁[0], y³ ₁[1], y³ ₁[2], y³ ₁[3], y³ ₁[4]}, and the bit vector for element y⁴ ₁ is {y⁴ ₁[0], y⁴ ₁[1], y⁴ ₁[2], y⁴ ₁[3], y⁴ ₁[4]}. Bit vector Y¹ 361 includes 4 bit vectors, i.e., bit vector elements 361 ⁰, 361 ¹, 361 ², 361 ³.

Bit vector Y² 362, bit vector Y³ 363, and bit vector Y⁴ 364 are formed in a similar manner from the second, third and fourth columns of matrix Y 360, respectively. Bit vector Y² 362 includes 4 bit vectors, i.e., bit vector elements 362 ⁰, 362 ¹, 362 ², 362 ³. Bit vector Y³ 363 includes 4 bit vectors, i.e., bit vector elements 363 ⁰, 363 ¹, 363 ², 363 ³. Bit vector Y⁴ 364 includes 4 bit vectors, i.e., bit vector elements 364 ⁰, 364 ¹, 364 ², 364 ³.

Bitslice vector set 460 includes bitslice vector BY¹ 461, bitslice vector BY² 462, bitslice vector BY³ 463 and bitslice vector BY⁴ 464.

Bitslice vector BY¹ 461 is formed from bit vector Y¹ 361, and includes bit vectors BY¹[0], BY¹[1], BY¹[2], BY¹[3], BY¹[4], i.e., bitslice vector elements 461 ⁰, 461 ¹, 461 ², 461 ³, 461 ⁴, respectively. Bitslice vector element 461 ⁰ is a sequence of bits formed from the bit at the first bit position of each element of bit vector Y 361, i.e., {y¹ ₁[0], y² ₁[0], y³ ₁[0], y⁴ ₁[0]}. Bitslice vector element 461 ¹ is a sequence of bits formed from the bit at the second bit position of each element of bit vector Y 361, i.e., {y¹ ₁[1], y² ₁[1], y³ ₁[1], y⁴ ₁[1]}. Bitslice vector element 461 ² is a sequence of bits formed from the bit at the third bit position of each element of bit vector Y 361, i.e., {y¹ ₁[2], y² ₁[2], y³ ₁[2], y⁴ ₁[2]}. Bitslice vector element 461 ³ is a sequence of bits formed from the bit at the fourth bit position of each element of bit vector Y 361, i.e., {y¹ ₁[3], y² ₁[3], y³ ₁[3], y⁴ ₁[3]}. Bitslice vector element 461 ⁴ is a sequence of bits formed from the bit at the fifth bit position of each element of bit vector Y 361, i.e., {y¹ ₁[4], y² ₁[4], y³ ₁[4], y⁴ ₁[4]}.

Bitslice vector BY² 462, bitslice vector BY³ 463 and bitslice vector BY⁴ 464 are formed in a similar manner from bit vector Y² 362, bit vector Y³ 363 and bit vector Y⁴ 364, respectively. Bitslice vector BY² 442 includes bit vectors BY²[0], BY²[1], BY²[2], BY²[3], BY²[4], i.e., bitslice vector elements 462 ⁰, 462 ¹, 462 ², 462 ³ and 462 ⁴, respectively. Bitslice vector BY³ 443 includes bit vectors BY³[0], BY³[1], BY³[2], BY³[3], BY³[4], i.e., bitslice vector elements 463 ⁰, 463 ¹, 463 ², 463 ³ and 463 ⁴, respectively. Bitslice vector BY⁴ 444 includes bit vectors BY⁴[0], BY⁴[1], BY⁴[2], BY⁴[3], BY⁴[4], i.e., bitslice vector elements 464 ⁰, 464 ¹, 464 ², 464 ³ and 464 ⁴, respectively.

Bitslice vector set 470 includes bitslice vector BY¹ 471, bitslice vector BY² 472, bitslice vector BY³ 473 and bitslice vector BY⁴ 474. Bitslice vector BY¹ 471 is formed from bitslice vector BY¹ 461 and includes bitslice vector elements 461 ⁰, 461 ¹, 461 ², 461 ³, 461 ⁴. Bitslice vector BY² 472 is formed from bitslice vector BY² 462 and includes bitslice vector elements 462 ⁰, 462 ¹, 462 ², 462 ³, 462 ⁴. Bitslice vector BY³ 473 is formed from bitslice vector BY³ 463 and includes bitslice vector elements 463 ⁰, 463 ¹, 463 ², 463 ³, 463 ⁴. Bitslice vector BY⁴ 474 is formed from bitslice vector BY⁴ 464 and includes bitslice vector elements 464 ⁰, 464 ¹, 464 ², 464 ³, 464 ⁴.

Bitslice tensor Y 475 is formed from bitslice vector BY¹ 471, bitslice vector BY² 472, bitslice vector BY³ 473, and bitslice vector BY⁴ 474.

FIGS. 9A and 9B depict data flow diagrams for OBDP array 650, while FIG. 9C depicts OBDP unit 500, in accordance with embodiments of the present disclosure.

In this embodiment, OBDP array 650 is an output stationary array that implements a bitslice dot product operation using a 4×4 array of single-bit dot product or one-bit dot product (OBDP) units 500, i.e., OBDP₁, OBDP₂, OBDP₃, OBDP₄, OBDP₅, OBDP₆, OBDP₇, OBDP₈, OBDP₉, OBDP₁₀, OBDP₁₁, OBDP₁₂, OBDP₁₃, OBDP₁₄, OBDP₁₅ and OBDP₁₆. Each OBDP unit 500 calculates a dot product between one row of matrix X and one column of matrix Y by multiplying certain elements of bitslice tensor X 455 and certain elements of bitslice tensor Y 475, in a particular sequence, and then outputting the result.

For example, OBDP₁ multiplies bitslice vector BX¹ 451 and bitslice vector BY¹ 471, accumulates the intermediate products and then generates the result. As described above, bitslice vector BX¹ 451 represents the elements of the first row of matrix X 340 (i.e., x¹ ₁, x¹ ₂, x¹ ₃ and x¹ ₄), and bitslice tensor BY¹ 471 represents the elements of the first column of matrix Y 360 340 (i.e., y¹ ₁, y² ₁, y³ ₁ and y⁴ ₁), and the result is zit. In addition to bitslice vector BX¹ 451 and bitslice vector BY¹ 471, the sum of indices j and k, i.e., “n”, and the sign parameter “s” are provided to OBDP₁.

OBDP array 650 may be a systolic or non-systolic array. FIG. 9A depicts the data flow for a non-systolic array that processes unsigned integers, while FIG. 9B depicts the data flow for a non-systolic array that processes signed integers. During each processing cycle, the appropriate element of bitslice tensor X 455 is provided to each OBDP unit 500 in each row, and the appropriate element of bitslice tensor Y 475 is provided to each OBDP unit 500 in each column. For example, during the first processing cycle (i.e., Cycle 1), bitslice vector 441 ⁰ (i.e., BX¹[0]) is provided to OBDP₁, OBDP₂, OBDP₃ and OBDP₄, while bitslice vector 461 ⁰ (i.e., BY₁[0]) is provided to OBDP₁, OBDP₅, OBDP₉ and OBDP₁₃.

OBDP unit 500 calculates the dot product between a row of a first matrix and a column of a second matrix with the same or different bit-width elements. In many embodiments, OBDP unit 500 is known as one-bit dot product unit 500.

OBDP unit 500 includes bitwise AND circuit 510, intermediate product circuit 520, adder circuit 530 and accumulator register 540. OBDP unit 500 receives a bitslice vector BX[j], a bitslice vector BY[k], and the parameters “n” and “s”. Bitwise AND circuit 510 performs a bitwise AND on BX[j] and BX[k] to generate an intermediate bit vector z. Intermediate product circuit 520 determines the number of ones in the intermediate bit vector z, left-shifts this count by index sum “n” and multiplies the left-shifted value by “s” to generate an intermediate product. Adder circuit 530 adds the intermediate value to the value stored in accumulator register 540, and then stores the accumulated value in accumulator register 540. FIG. 9A illustrates the multiplication of unsigned operands for which the sign parameter 2 is equal to 1, while FIG. 9B illustrates the multiplication of signed operands for which the sign parameter 2 is equal to 1 or −1 based on the most significant bits of the operands, as discussed above and as provided in Table 1.

FIGS. 10A and 10B depict a first example of the multiplication of matrix X 340 and matrix Y 360 to generate matrix Z 380 using OBDP array 650, in accordance with an embodiment of the present disclosure.

Matrix X 340 includes sixteen 3-bit unsigned integer elements, i.e., x¹ ₁, x¹ ₂, x¹ ₃, x¹ ₄, x² ₁, x² ₂, x² ₃, x² ₄, x³ ₁, x³ ₂, x³ ₃, x³ ₄, x⁴ ₁, x⁴ ₂, x⁴ ₃ and x⁴ ₄, all of which are equal to 1 (i.e., binary “001”). Matrix Y 360 includes sixteen 5-bit unsigned integer elements, i.e., y¹ ₁, y² ₁, y³ ₁, y⁴ ₁, y¹ ₂, y² ₂, y³ ₂, y⁴ ₂, y¹ ₃, y² ₃, y³ ₃, y⁴ ₃, y¹ ₄, y² ₄, y³ ₄ and y⁴ ₄, all of which are equal to 1 (i.e., binary “00001”). Matrix Z 380 includes sixteen 32-bit unsigned integer elements, i.e., z¹ ₁, z¹ ₂, z¹ ₃, z¹ ₄, z² ₁, z² ₂, z² ₃, z² ₄, z³ ₁, z³ ₂, z³ ₃, z³ ₄, z⁴ ₁, z⁴ ₂, z⁴ ₃ and z⁴ ₄. Result matrix 382 presents the result of multiplying the decimal values of matrix X 340 and matrix Y 360 (i.e., the “direct calculation”); the values of all of the elements of result matrix 382 are equal to 4. Difference matrix 383 presents the differences between the individual elements of result matrix 382 and the elements calculated by computation array 384 (depicted in FIG. 10B); all of the elements of difference matrix 383 are equal to 0.

Bitslice vectors 441 ⁰, 441 ¹ and 441 ² of bitslice vector BX¹ 451, bitslice vectors 442 ⁰, 442 ¹ (not labeled for clarity) and 442 ² of bitslice vector BX² 452, bitslice vectors 443 ⁰, 443 ¹ (not labeled for clarity) and 443 ² of bitslice vector BX³ 453, and bitslice vectors 444 ⁰, 444 ¹ (not labeled for clarity) and 444 ² of bitslice vector BX⁴ 454 are depicted.

Similarly, bitslice vectors 461 ⁰, 461 ¹ (not labeled for clarity), 461 ² (not labeled for clarity), 461 ³ (not labeled for clarity) and 461 ⁴ of bitslice vector BY¹ 471, bitslice vectors 462 ⁰, 462 ¹ (not labeled for clarity), 462 ² (not labeled for clarity), 462 ³ (not labeled for clarity) and 462 ⁴ of bitslice vector BY² 472, bitslice vectors 463 ⁰, 463 ¹ (not labeled for clarity), 463 ² (not labeled for clarity), 463 ³ (not labeled for clarity) and 463 ⁴ of bitslice vector BY³ 473, and bitslice vectors 464 ⁰, 464 ¹, 464 ², 464 ³ and 464 ⁴ of bitslice vector BY⁴ 474 are depicted.

Computation array 384 depicts the computation of the bitslice dot product between a respective row of matrix X 340 and a respective column of matrix Y 360 by each OBDP unit 500 in OBDP array 650. The dot product computation is described above with respect to one-bit dot product unit 400.

The value for each element of matrix z 380 depicted in FIG. 10B, i.e., z¹ ₁, z¹ ₂, z¹ ₃, z¹ ₄, z² ₁, z² ₂, z² ₃, z² ₄, z³ ₁, z³ ₂, z³ ₃, z³ ₄, z⁴ ₁, z⁴ ₂, z⁴ ₃ and z⁴ ₄, are depicted in a box directly beneath the element name. The values of all of the elements of matrix z 380 are equal to 4, and match the values of the elements of results matrix 382 depicted in FIG. 10A.

FIGS. 10C and 10D depict a second example of the multiplication of matrix X 340 and matrix Y 360 to generate matrix Z 380 using OBDP array 650, in accordance with an embodiment of the present disclosure.

Matrix X 340 includes sixteen 3-bit unsigned integer elements, i.e., x¹ ₁, x¹ ₂, x¹ ₃, x¹ ₄, x² ₁, x² ₂, x² ₃, x² ₄, x³ ₁, x³ ₂, x³ ₃, x³ ₄, x⁴ ₁, x⁴ ₂, x⁴ ₃ and x⁴ ₄, all of which are equal to 7 (i.e., binary “111”). Matrix Y 360 includes sixteen 5-bit unsigned integer elements, i.e., y¹ ₁, y² ₁, y³ ₁, y⁴ ₁, y¹ ₂, y² ₂, y³ ₂, y⁴ ₂, y¹ ₃, y² ₃, y³ ₃, y⁴ ₃, y¹ ₄, y² ₄, y³ ₄ and y⁴ ₄, all of which are equal to 31 (i.e., binary “11111”). Matrix Z 380 includes sixteen 32-bit unsigned integer elements, i.e., z¹ ₁, z¹ ₂, z¹ ₃, z¹ ₄, z² ₁, z² ₂, z² ₃, z² ₄, z³ ₁, z³ ₂, z³ ₃, z³ ₄, z⁴ ₁, z⁴ ₂, z⁴ ₃ and z⁴ ₄. Result matrix 382 presents the result of multiplying the decimal values of matrix X 340 and matrix Y 360; the values of all of the elements of result matrix 382 are equal to 868. Difference matrix 383 presents the differences between the individual elements of result matrix 382 and the elements calculated by computation array 384 (depicted in FIG. 10D); all of the elements of difference matrix 383 are equal to 0.

Bitslice vectors 441 ⁰, 441 ¹ and 441 ² of bitslice vector BX¹ 451, bitslice vectors 442 ⁰, 442 ¹ (not labeled for clarity) and 442 ² of bitslice vector BX² 452, bitslice vectors 443 ⁰, 443 ¹ (not labeled for clarity) and 443 ² of bitslice vector BX³ 453, and bitslice vectors 444 ⁰, 444 ¹ (not labeled for clarity) and 444 ² of bitslice vector BX⁴ 454 are depicted.

Similarly, bitslice vectors 461 ⁰, 461 ¹ (not labeled for clarity), 461 ² (not labeled for clarity), 461 ³ (not labeled for clarity) and 461 ⁴ of bitslice vector BY¹ 471, bitslice vectors 462 ⁰, 462 ¹ (not labeled for clarity), 462 ² (not labeled for clarity), 462 ³ (not labeled for clarity) and 462 ⁴ of bitslice vector BY² 472, bitslice vectors 463 ⁰, 463 ¹ (not labeled for clarity), 463 ² (not labeled for clarity), 463 ³ (not labeled for clarity) and 463 ⁴ of bitslice vector BY³ 473, and bitslice vectors 464 ⁰, 464 ¹, 464 ², 464 ³ and 464 ⁴ of bitslice vector BY⁴ 474 are depicted.

Computation array 384 depicts the computation of the bitslice dot product between a respective row of matrix X 340 and a respective column of matrix Y 360 by each OBDP unit 500 in OBDP array 650. The dot product computation is described above with respect to one-bit dot product unit 400.

The value for each element of matrix z 380 depicted in FIG. 10D, i.e., z¹ ₁, z¹ ₂, z¹ ₃, z¹ ₄, z² ₁, z² ₂, z² ₃, z² ₄, z³ ₁, z³ ₂, z³ ₃, z³ ₄, z⁴ ₁, z⁴ ₂, z⁴ ₃ and z⁴ ₄, are depicted in a box directly beneath the element name. The values of all of the elements of matrix z 380 are equal to 868, and match the values of the elements of results matrix 382 depicted in FIG. 10C.

FIGS. 10E and 10F depict a third example of the multiplication of matrix X 340 and matrix Y 360 to generate matrix Z 380 using OBDP array 650, in accordance with an embodiment of the present disclosure.

Matrix X 340 includes sixteen 3-bit unsigned integer elements, i.e., x¹ ₁, x¹ ₂, x¹ ₃, x¹ ₄, x² ₁, x² ₂, x² ₃, x² ₄, x³ ₁, x³ ₂, x³ ₃, x³ ₄, x⁴ ₁, x⁴ ₂, x⁴ ₃ and x⁴ ₄. Element x¹ ₁ is equal to 0 (i.e., binary “000”), x¹ ₂ is equal to 1 (i.e., binary “001”), x¹ ₃ is equal to 1 (i.e., binary “001”), x¹ ₄ is equal to 0 (i.e., binary “000”), x² ₁ is equal to 3 (i.e., binary “011”), x² ₂ is equal to 7 (i.e., binary “111”), x² ₃ is equal to 7 (i.e., binary “111”), x² ₄ is equal to 3 (i.e., binary “011”), x³ ₁ is equal to 3 (i.e., binary “011”), x³ ₂ is equal to 7 (i.e., binary “111”), x³ ₃ is equal to 7 (i.e., binary “111”), x³ ₄ is equal to 3 (i.e., binary “011”), x⁴ ₁ is equal to 0 (i.e., binary “000”), x⁴ ₂ is equal to 1 (i.e., binary “001”), x⁴ ₃ is equal to 1 (i.e., binary “001”), and x⁴ ₄ is equal to 0 (i.e., binary “000”).

Matrix Y 360 includes sixteen 5-bit unsigned integer elements, i.e., y¹ ₁, y² ₁, y³ ₁, y⁴ ₁, y¹ ₂, y² ₂, y³ ₂, y⁴ ₂, y¹ ₃, y² ₃, y³ ₃, y⁴ ₃, y¹ ₄, y² ₄, y³ ₄ and y⁴ ₄. Element y¹ ₁ is equal to 1 (i.e., binary “00001”), y² ₁ is equal to 2 (i.e., binary “00010”), y³ ₁ is equal to 2 (i.e., binary “00010”), y⁴ ₁ is equal to 1 (i.e., binary “00001”), y¹ ₂ is equal to 3 (i.e., binary “00011”), y² ₂ is equal to 6 (i.e., binary “00110”), y³ ₂ is equal to 6 (i.e., binary “00110”), y⁴ ₂ is equal to 3 (i.e., binary “00011”), y¹ ₃ is equal to 3 (i.e., binary “00011”), y² ₃ is equal to 9 (i.e., binary “01001”), y³ ₃ is equal to 9 (i.e., binary “01001”), y⁴ ₃ is equal to 3 (i.e., binary “00011”), y¹ ₄ is equal to 1 (i.e., binary “00001”), y² ₄ is equal to 2 (i.e., binary “0010”), y³ ₄ is equal to 2 (i.e., binary “00010”), and y⁴ ₄ is equal to 1 (i.e., binary “00001”).

Matrix Z 380 includes sixteen 32-bit unsigned integer elements, i.e., z¹ 1, z¹ ₂, z¹ ₃, z¹ ₄, z² ₁, z² ₂, z² ₃, z² ₄, z³ ₁ z³ ₂, z³ ₃, z³ ₄, z⁴ ₁, z⁴ ₂, z⁴ ₃ and z⁴ ₄. Result matrix 382 presents the result of multiplying the decimal values of matrix X 340 and matrix Y 360. Difference matrix 383 presents the differences between the individual elements of result matrix 382 and the elements calculated by computation array 384 (depicted in FIG. 10F); all of the elements of difference matrix 383 are equal to 0.

Bitslice vectors 441 ⁰, 441 ¹ and 441 ² of bitslice vector BX¹ 451, bitslice vectors 442 ⁰, 442 ¹ (not labeled for clarity) and 442 ² of bitslice vector BX² 452, bitslice vectors 443 ⁰, 443 ¹ (not labeled for clarity) and 443 ² of bitslice vector BX³ 453, and bitslice vectors 444 ⁰, 444 ¹ (not labeled for clarity) and 444 ² of bitslice vector BX⁴ 454 are depicted.

Similarly, bitslice vectors 461 ⁰, 461 ¹ (not labeled for clarity), 461 ² (not labeled for clarity), 461 ³ (not labeled for clarity) and 461 ⁴ of bitslice vector BY¹ 471, bitslice vectors 462 ⁰, 462 ¹ (not labeled for clarity), 462 ² (not labeled for clarity), 462 ³ (not labeled for clarity) and 462 ⁴ of bitslice vector BY² 472, bitslice vectors 463 ⁰, 463 ¹ (not labeled for clarity), 463 ² (not labeled for clarity), 463 ³ (not labeled for clarity) and 463 ⁴ of bitslice vector BY³ 473, and bitslice vectors 464 ⁰, 464 ¹, 464 ², 464 ³ and 464 ⁴ of bitslice vector BY⁴ 474 are depicted.

Computation array 384 depicts the computation of the bitslice dot product between a respective row of matrix X 340 and a respective column of matrix Y 360 by each OBDP unit 500 in OBDP array 650. The dot product computation is described above with respect to one-bit dot product unit 400.

The value for each element of matrix z 380 depicted in FIG. 10F, i.e., z¹ ₁, z¹ ₂, z¹ ₃, z¹ ₄, z² ₁, z² ₂, z² ₃, z² ₄, z³ ₁, z³ ₂, z³ ₃, z³ ₄, z⁴ ₁, z⁴ ₂, z⁴ ₃ and z⁴ ₄, are depicted in a box directly beneath the element name, i.e., 4, 12, 18, 4, 34, 102, 144, 34, 34, 102, 144, 34, 4, 12, 18 and 4, respectively. The values of all of the elements of matrix z 380 match the values of the elements of results matrix 382 depicted in FIG. 10E.

FIGS. 10G and 10H depict a fourth example of the multiplication of matrix X 340 and matrix Y 360 to generate matrix Z 380 using OBDP array 650, in accordance with an embodiment of the present disclosure.

Matrix X 340 includes sixteen 3-bit signed integer elements, i.e., x¹ ₁, x¹ ₂, x¹ ₃, x¹ ₄, x² ₁, x² ₂, x² ₃, x² ₄, x³ ₁, x³ ₂, x³ ₃, x³ ₄, x⁴ ₁, x⁴ ₂, x⁴ ₃ and x⁴ ₄; elements x¹ ₁, x¹ ₂, x¹ ₃, x¹ ₄, x² ₁, x² ₂, x² ₃ and x² ₄, are equal to −1 (i.e., binary “111”), and elements x³ ₁, x³ ₂, x³ ₃, x³ ₄, x⁴ ₁, x⁴ ₂, x⁴ ₃ and x⁴ ₄ are equal to 1 (i.e., binary “001”). Matrix Y 360 includes sixteen 5-bit signed integer elements, i.e., y¹ ₁, y² ₁, y³ ₁, y⁴ ₁, y¹ ₂, y² ₂, y³ ₂, y⁴ ₂, y¹ ₃, y² ₃, y³ ₃, y⁴ ₃, y¹ ₄, y² ₄, y³ ₄ and y⁴ ₄; elements y¹ ₁, y² ₁, y³ ₁, y⁴ ₁, y¹ ₂, y² ₂, y³ ₂ and y⁴ ₂ are equal to 1 (i.e., binary “00001”), and elements y¹ ₃, y² ₃, y³ ₃, y⁴ ₃, y¹ ₄, y² ₄, y³ ₄ and y⁴ ₄ are equal to −1 (i.e., binary “11111”). Matrix Z 380 includes sixteen 32-bit signed integer elements, i.e., z¹ ₁, z¹ ₂, z¹ ₃, z¹ ₄, z² ₁, z² ₂, z² ₃, z² ₄, z³ ₁ z³ ₂, z³ ₃, z³ ₄ z⁴ ₁ z⁴ ₂, z⁴ ₃ and z⁴ ₄. Result matrix 382 presents the result of multiplying the decimal values of matrix X 340 and matrix Y 360. Difference matrix 383 presents the differences between the individual elements of result matrix 382 and the elements calculated by computation array 384 (depicted in FIG. 10H); all of the elements of difference matrix 383 are equal to 0.

Bitslice vectors 441 ⁰, 441 ¹ and 441 ² of bitslice vector BX¹ 451, bitslice vectors 442 ⁰, 442 ¹ (not labeled for clarity) and 442 ² of bitslice vector BX² 452, bitslice vectors 443 ⁰, 443 ¹ (not labeled for clarity) and 443 ² of bitslice vector BX³ 453, and bitslice vectors 444 ⁰, 444 ¹ (not labeled for clarity) and 444 ² of bitslice vector BX⁴ 454 are depicted.

Similarly, bitslice vectors 461 ⁰, 461 ¹ (not labeled for clarity), 461 ² (not labeled for clarity), 461 ³ (not labeled for clarity) and 461 ⁴ of bitslice vector BY¹ 471, bitslice vectors 462 ⁰, 462 ¹ (not labeled for clarity), 462 ² (not labeled for clarity), 462 ³ (not labeled for clarity) and 462 ⁴ of bitslice vector BY² 472, bitslice vectors 463 ⁰, 463 ¹ (not labeled for clarity), 463 ² (not labeled for clarity), 463 ³ (not labeled for clarity) and 463 ⁴ of bitslice vector BY³ 473, and bitslice vectors 464 ⁰, 464 ¹, 464 ², 464 ³ and 464 ⁴ of bitslice vector BY⁴ 474 are depicted.

Computation array 384 depicts the computation of the bitslice dot product between a respective row of matrix X 340 and a respective column of matrix Y 360 by each OBDP unit 500 in OBDP array 650. The dot product computation is described above with respect to one-bit dot product unit 400.

The value for each element of matrix z 380 depicted in FIG. 10H, i.e., z¹ ₁, z¹ ₂, z¹ ₃, z¹ ₄, z² ₁, z² ₂, z² ₃, z² ₄, z³ ₁ z³ ₂, z³ ₃, z³ ₄ z⁴ ₁ z⁴ ₂, z⁴ ₃ and z⁴ ₄, are depicted in a box directly beneath the element name, i.e., −4, −4, 4, 4, −4, −4, 4, 4, 4, 4, −4, −4, 4, 4, −4 and −4, respectively. The values of all of the elements of matrix z 380 match the values of the elements of results matrix 382 depicted in FIG. 10G.

FIGS. 10I and 10J depict a fifth example of the multiplication of matrix X 340 and matrix Y 360 to generate matrix Z 380 using OBDP array 650, in accordance with an embodiment of the present disclosure.

Matrix X 340 includes sixteen 3-bit signed integer elements, i.e., x¹ ₁, x¹ ₂, x¹ ₃, x¹ ₄, x² ₁, x² ₂, x² ₃, x² ₄, x³ ₁, x³ ₂, x³ ₃, x³ ₄, x⁴ ₁, x⁴ ₂, x⁴ ₃ and x⁴ ₄; elements x¹ ₁, x¹ ₂, x¹ ₃, x¹ ₄, x² ₁, x² ₂, x² ₃ and x² ₄, are equal to 3 (i.e., binary “011”), and elements x³ ₁, x³ ₂, x³ ₃, x³ ₄, x⁴ ₁, x⁴ ₂, x⁴ ₃ and x⁴ ₄ are equal to −4 (i.e., binary “100”). Matrix Y 360 includes sixteen 5-bit signed integer elements, i.e., y¹ ₁, y² ₁, y³ ₁, y⁴ ₁, y¹ ₂, y² ₂, y³ ₂, y⁴ ₂, y¹ ₃, y² ₃, y³ ₃, y⁴ ₃, y¹ ₄, y² ₄, y³ ₄ and y⁴ ₄; elements y¹ ₁, y² ₁, y³ ₁, y⁴ ₁, y¹ ₂, y² ₂, y³ ₂ and y⁴ ₂ are equal to −16 (i.e., binary “10000”), and elements y¹ ₃, y² ₃, y³ ₃, y⁴ ₃, y¹ ₄, y² ₄, y³ ₄ and y⁴ ₄ are equal to 15 (i.e., binary “01111”). Matrix Z 380 includes sixteen 32-bit signed integer elements, i.e., z¹ ₁, z¹ ₂, z¹ ₃, z¹ ₄, z² ₁, z² ₂, z² ₃, z² ₄, z³ ₁ z³ ₂, z³ ₃, z³ ₄ z⁴ ₁ z⁴ ₂, z⁴ ₃ and z⁴ ₄. Result matrix 382 presents the result of multiplying the decimal values of matrix X 340 and matrix Y 360. Difference matrix 383 presents the differences between the individual elements of result matrix 382 and the elements calculated by computation array 384 (depicted in FIG. 10J); all of the elements of difference matrix 383 are equal to 0.

Bitslice vectors 441 ⁰, 441 ¹ and 441 ² of bitslice vector BX¹ 451, bitslice vectors 442 ⁰, 442 ¹ (not labeled for clarity) and 442 ² of bitslice vector BX² 452, bitslice vectors 443 ⁰, 443 ¹ (not labeled for clarity) and 443 ² of bitslice vector BX³ 453, and bitslice vectors 444 ⁰, 444 ¹ (not labeled for clarity) and 444 ² of bitslice vector BX⁴ 454 are depicted.

Similarly, bitslice vectors 461 ⁰, 461 ¹ (not labeled for clarity), 461 ² (not labeled for clarity), 461 ³ (not labeled for clarity) and 461 ⁴ of bitslice vector BY¹ 471, bitslice vectors 462 ⁰, 462 ¹ (not labeled for clarity), 462 ² (not labeled for clarity), 462 ³ (not labeled for clarity) and 462 ⁴ of bitslice vector BY² 472, bitslice vectors 463 ⁰, 463 ¹ (not labeled for clarity), 463 ² (not labeled for clarity), 463 ³ (not labeled for clarity) and 463 ⁴ of bitslice vector BY³ 473, and bitslice vectors 464 ⁰, 464 ¹, 464 ², 464 ³ and 464 ⁴ of bitslice vector BY⁴ 474 are depicted.

Computation array 384 depicts the computation of the bitslice dot product between a respective row of matrix X 340 and a respective column of matrix Y 360 by each OBDP unit 500 in OBDP array 650. The dot product computation is described above with respect to one-bit dot product unit 400.

The value for each element of matrix z 380 depicted in FIG. 10J, i.e., z¹ ₁, z¹ ₂, z¹ ₃, z¹ ₄, z² ₁, z² ₂, z² ₃, z² ₄, z³ ₁, z³ ₂, z³ ₃, z³ ₄, z⁴ ₁, z⁴ ₂, z⁴ ₃ and z⁴ ₄, are depicted in a box directly beneath the element name, i.e., −192, −192, 180, 180, −192, −192, 180, 180, 256, 256, −240, −240, 256, 256, −240 and −240, respectively. The values of all of the elements of matrix z 380 match the values of the elements of results matrix 382 depicted in FIG. 10I.

FIGS. 10K and 10L depict a sixth example of the multiplication of matrix X 340 and matrix Y 360 to generate matrix Z 380 using OBDP array 650, in accordance with an embodiment of the present disclosure.

Matrix X 340 includes sixteen 3-bit signed integer elements, i.e., x¹ ₁, x¹ ₂, x¹ ₃, x¹ ₄, x² ₁, x² ₂, x² ₃, x² ₄, x³ ₁, x³ ₂, x³ ₃, x³ ₄, x⁴ ₁, x⁴ ₂, x⁴ ₃ and x⁴ ₄. Element x¹ ₁ is equal to −4 (i.e., binary “100”), x¹ ₂ is equal to −3 (i.e., binary “101”), x¹ ₃ is equal to −2 (i.e., binary “110”), x¹ ₄ is equal to −1 (i.e., binary “111”), x² ₁ is equal to 0 (i.e., binary “000”), x² ₂ is equal to 1 (i.e., binary “001”), x² ₃ is equal to 2 (i.e., binary “111”), x² ₄ is equal to 3 (i.e., binary “011”), x³ ₁ is equal to 3 (i.e., binary “011”), x³ ₂ is equal to 2 (i.e., binary “010”), x³ ₃ is equal to 1 (i.e., binary “001”), x³ ₄ is equal to 0 (i.e., binary “000”), x⁴ ₁ is equal to −1 (i.e., binary “111”), x⁴ ₂ is equal to −2 (i.e., binary “110”), x⁴ ₃ is equal to −3 (i.e., binary “101”), and x⁴ ₄ is equal to −4 (i.e., binary “100”).

Matrix Y 360 includes sixteen 5-bit signed integer elements, i.e., y¹ ₁, y³ ₁, y⁴ ₁, y¹ ₂, y² ₂, y³ ₂, y⁴ ₂, y¹ ₃, y² ₃, y³ ₃, y⁴ ₃, y¹ ₄, y² ₄, y³ ₄ and y⁴ ₄. Element y¹ ₁ is equal to 15 (i.e., binary “01111”), y² ₁ is equal to 13 (i.e., binary “01101”), y³ ₁ is equal to 11 (i.e., binary “01011”), y⁴ ₁ is equal to 9 (i.e., binary “01001”), y¹ ₂ is equal to 7 (i.e., binary “00111”), y² ₂ is equal to 5 (i.e., binary “00101”), y³ ₂ is equal to 3 (i.e., binary “00011”), y⁴ ₂ is equal to 1 (i.e., binary “00001”), y¹ ₃ is equal to −2 (i.e., binary “11110”), y² ₃ is equal to −4 (i.e., binary “11100”), y³ ₃ is equal to −6 (i.e., binary “11010”), y⁴ ₃ is equal to −8 (i.e., binary “11000”), y¹ ₄ is equal to −10 (i.e., binary “10110”), y² ₄ is equal to −12 (i.e., binary “10100”), y³ ₄ is equal to −14 (i.e., binary “10010”), and y⁴ ₄ is equal to −16 (i.e., binary “10000”).

Matrix Z 380 includes sixteen 32-bit signed integer elements, i.e., z¹ ₁, z¹ ₂, z¹ ₃, z¹ ₄, z² ₁, z² ₂, z² ₃, z² ₄, z³ ₁ z³ ₂, z³ ₃, z³ ₄ z⁴ ₁ z⁴ ₂, z⁴ ₃ and z⁴ ₄. Result matrix 382 presents the result of multiplying the decimal values of matrix X 340 and matrix Y 360. Difference matrix 383 presents the differences between the individual elements of result matrix 382 and the elements calculated by computation array 384 (depicted in FIG. 10L); all of the elements of difference matrix 383 are equal to 0.

Bitslice vectors 441 ⁰, 441 ¹ and 441 ² of bitslice vector BX¹ 451, bitslice vectors 442 ⁰, 442 ¹ (not labeled for clarity) and 442 ² of bitslice vector BX² 452, bitslice vectors 443 ⁰, 443 ¹ (not labeled for clarity) and 443 ² of bitslice vector BX³ 453, and bitslice vectors 444 ⁰, 444 ¹ (not labeled for clarity) and 444 ² of bitslice vector BX⁴ 454 are depicted.

Similarly, bitslice vectors 461 ⁰, 461 ¹ (not labeled for clarity), 461 ² (not labeled for clarity), 461 ³ (not labeled for clarity) and 461 ⁴ of bitslice vector BY¹ 471, bitslice vectors 462 ⁰, 462 ¹ (not labeled for clarity), 462 ² (not labeled for clarity), 462 ³ (not labeled for clarity) and 462 ⁴ of bitslice vector BY² 472, bitslice vectors 463 ⁰, 463 ¹ (not labeled for clarity), 463 ² (not labeled for clarity), 463 ³ (not labeled for clarity) and 463 ⁴ of bitslice vector BY³ 473, and bitslice vectors 464 ⁰, 464 ¹, 464 ², 464 ³ and 464 ⁴ of bitslice vector BY⁴ 474 are depicted.

Computation array 384 depicts the computation of the bitslice dot product between a respective row of matrix X 340 and a respective column of matrix Y 360 by each OBDP unit 500 in OBDP array 650. The dot product computation is described above with respect to one-bit dot product unit 400.

The value for each element of matrix z 380 depicted in FIG. 10L, i.e., z¹ ₁, z¹ ₂, z¹ ₃, z¹ ₄, z² ₁, z² ₂, z² ₃, z² ₄, z³ ₁ z³ ₂, z³ ₃, z³ ₄ z⁴ ₁ z⁴ ₂, z⁴ ₃ and z⁴ ₄, are depicted in a box directly beneath the element name, i.e., −130, −50, 40, 120, 62, 14, −40, −88, 82, 34, −20, −68, −110, −30, 60 and 140, respectively. The values of all of the elements of matrix z 380 match the values of the elements of results matrix 382 depicted in FIG. 10K.

FIG. 11 depicts a block diagram of MMA 600, in accordance with embodiments of the present disclosure.

MMA 600 includes I/O interface 605, processor or controller 610, memory 615, register 620, register 630, register 640 and OBDP array 650.

In this embodiment, OBDP array 650 includes 16 OBDP units 500 arranged in a 4×4 array; other numbers of OBDP units 500 and arrangements are also contemplated, such as, for example, four OBDP units 500 arranged in a 2×2 array, nine OBDP units 500 arranged in a 3×3 array, 25 OBDP units 500 arranged in a 5×5 array, 36 OBDP units 500 arranged in a 6×6 array, 49 OBDP units 500 arranged in a 7×7 array, 64 OBDP units 500 arranged in a 8×8 array, etc. Non-symmetric arrangements, such as a 2×3 array, a 3×4 array, a 4×5 array, a 4×6 array, etc., may be advantageous for certain applications. Each OBDP unit 500 is coupled to register 620, register 630 and register 640, and calculates a dot product for one element of converted output data matrix 216. In certain embodiments, each OBDP unit 500 may be coupled to a single register (not depicted for clarity), while in other embodiments, each OBDP unit 500 may be directly (or indirectly) coupled to memory 615. Other configurations are also supported.

For example, the OBDP unit 500 located in the first row and the first column (i.e., OBDP₁) of OBDP array 650 may calculate the dot products of the 1st row of converted weight matrix 212 and the 1^(st), 5^(th), 9^(th) and 13^(th) columns of converted input data matrix 214, using bitslice tensor matrices, to generate the o¹ ₁, o¹ ₅, o¹ ₉ and o¹ ₁₃ elements of converted output data matrix 216.

I/O interface 605 is coupled to bus 710, controller 610 and storage (such as memory 615). I/O interface 605 includes a microcontroller that sends data to, and receives data and commands from, processor 720, storage (such as memory 730), etc. The microcontroller implements a set of instructions that controls the data flow and the operation of OBDP units 500.

In some embodiments, a dedicated controller, microcontroller, field programmable gate array (FPGA), etc., may control the data flow and the operation of MMA 600. For example, the controller may implement load/store (L/S) instructions, memory mapped I/O (MMIO), direct memory access (DMA), etc., to load elements of bitslice tensor X 455 and associated data into register 620, to load elements of bitslice tensor Y 475 and associated data into register 630, start the matrix multiply operation, read back the output matrix from register 640, etc. In one embodiment, a software module executing on a CPU, such as, for example, processor 720, calculates the bitslice tensors and related data for each matrix, and then sends these data and the appropriate commands to MMA 600 to upload memory 615, registers 620 and 630, start the matrix multiply operation, read back the results from register 640, etc. In another embodiment, the software module executing on the CPU sends the matrices to MMA 600, and then controller 610 calculates the bitslice tensor data and related data (e.g., n, s) for each matrix, uploads registers 620 and 630, start the matrix multiply operation, reads back the results from register 640, etc.

Generally, register 620 simultaneously provides certain data from bitslice tensor X 455 to each row of OBDP units 500 in OBDP array 650, register 630 simultaneously provides certain data from bitslice tensor Y 475 and other related data (i.e., n, s) to each column of OBDP units 500 in OBDP array 650, and register 640 stores the elements of the output matrix in the multiplication operation.

In other embodiments, rather then the circuitry depicted in FIG. 9C, each OBDP unit 500 includes a processor that executes the dot product computation described above with respect to one-bit dot product unit 400.

FIG. 12 depicts a block diagram of system 700, in accordance with an embodiment of the present disclosure.

Computer 702 includes bus 710 coupled to one or more processors 720, memory 730, I/O interfaces 740, display interface 750, one or more communication interfaces 760 and one or more MMAs 600. Generally, I/O interfaces 740 are coupled to I/O devices 742 using a wired or wireless connection, display interface 750 is coupled to display 752, and communication interface 760 is connected to network 762 using a wired or wireless connection.

Bus 710 is a communication system that transfers data between processor 720, memory 730, I/O interfaces 740, display interface 750, communication interface 760, MMA 600, as well as other components not depicted in FIG. 12 . Power connector 712 is coupled to bus 710 and a power supply (not shown).

Processor 720 includes one or more general-purpose or application-specific microprocessors that executes instructions to perform control, computation, input/output, etc. functions for computer 702. Processor 720 may include a single integrated circuit, such as a micro-processing device, or multiple integrated circuit devices and/or circuit boards working in cooperation to accomplish the functions of processor 720. In addition, processor 720 may execute computer programs or modules, such as operating system 732, software modules 734, etc., stored within memory 730. For example, software modules 734 may include an ML application, an ANN application, a CNN application, etc.

Generally, storage element or memory 730 stores instructions for execution by processor 720 and data. Memory 730 may include a variety of non-transitory computer-readable medium that may be accessed by processor 720. In various embodiments, memory 730 may include volatile and nonvolatile medium, non-removable medium and/or removable medium. For example, memory 730 may include any combination of random access memory (RAM), dynamic RAM (DRAM), static RAM (SRAM), read only memory (ROM), flash memory, cache memory, and/or any other type of non-transitory computer-readable medium.

Memory 730 contains various components for retrieving, presenting, modifying, and storing data. For example, memory 730 stores software modules that provide functionality when executed by processor 720. The software modules include operating system 732 that provides operating system functionality for computer 702. Software modules 734 provide various functionality, such as image classification using convolutional neural networks, etc. Data 736 may include data associated with operating system 732, software modules 734, etc.

I/O interfaces 740 are configured to transmit and/or receive data from I/O devices 742. I/O interfaces 740 enable connectivity between processor 720 and I/O devices 742 by encoding data to be sent from processor 720 to I/O devices 742, and decoding data received from I/O devices 742 for processor 720. Generally, data may be sent over wired and/or wireless connections. For example, I/O interfaces 740 may include one or more wired communications interfaces, such as USB, Ethernet, etc., and/or one or more wireless communications interfaces, coupled to one or more antennas, such as WiFi, Bluetooth, cellular, etc.

Generally, I/O devices 742 provide input to computer 702 and/or output from computer 702. As discussed above, I/O devices 742 are operably connected to computer 702 using a wired and/or wireless connection. I/O devices 742 may include a local processor coupled to a communication interface that is configured to communicate with computer 702 using the wired and/or wireless connection. For example, I/O devices 742 may include a keyboard, mouse, touch pad, joystick, etc.

Display interface 750 is configured to transmit image data from computer 702 to monitor or display 752.

Communication interface 760 is configured to transmit data to and from network 762 using one or more wired and/or wireless connections. Network 762 may include one or more local area networks, wide area networks, the Internet, etc., which may execute various network protocols, such as, for example, wired and/or wireless Ethernet, Bluetooth, etc. Network 762 may also include various combinations of wired and/or wireless physical layers, such as, for example, copper wire or coaxial cable networks, fiber optic networks, Bluetooth wireless networks, WiFi wireless networks, CDMA, FDMA and TDMA cellular wireless networks, etc.

MMA 600 is configured to multiply matrices and generate output matrices to support various applications implemented by software modules 734. In certain embodiments, MMA 600 is not needed and processor 720 executes the dot product computation described above with respect to one-bit dot product unit 400.

The embodiments described herein are combinable.

In one embodiment, a processor obtains a first bitslice vector comprising m elements, where each element is a bit vector having a plurality of bits, where each bit corresponds to a bit value at a particular bit position of a respective m-bit operand of a number of m-bit operands; obtains a second bitslice vector comprising n elements, where each element is a bit vector having a plurality of bits, where each bit corresponds to a bit value at a particular bit position of a respective n-bit operand of a number of n-bit operands, where n and m are greater than one; provides at least one element of the first bitslice vector as a first input to a single bit dot product unit; provides at least one element of the second bit-slice vector as a second input to the single-bit dot product unit; and obtains, from the single-bit dot product unit, an output comprising at least a partial dot product of the first and second bitslice vectors.

In another embodiment of the processor, provide at least one element of the first bitslice vector includes provide the elements of the first bitslice vector in a first sequence; provide at least one element of the second bitslice vector includes provide the elements of the second bitslice vector in a second sequence; and the output is a dot product of the first and second bitslice vectors.

In another embodiment of the processor, obtain the first bit-slice vector includes read the first bit vector from a storage; and obtain the second bit-slice vector includes read the second bit vector from the storage.

In another embodiment of the processor, obtain the first bit-slice vector includes for each m-bit operand, generate a bit vector having m bits, each bit corresponding to a bit value at a particular bit position of the m-bit operand, and generate the first bitslice vector based on the bit vectors for the m bit operands; and obtain the second bit-slice vector includes for each n-bit operand, generate a bit vector having n bits, each bit corresponding to a bit value at a particular bit position of the n-bit operand, and generate the second bitslice vector based on the bit vectors for the n bit operands.

In another embodiment of the processor, the number of m-bit operands is the same as the number of n-bit operands.

In another embodiment of the processor, m is less than n.

In another embodiment of the processor, the processor obtains a first bitslice tensor based on a first matrix, the first bitslice tensor including a number of first bitslice vectors, each first bitslice vector corresponding to a row of the first matrix, each row of the first matrix having the number of m-bit operands; obtains a second bitslice tensor based on a second matrix, the second bitslice tensor including a number of second bitslice vectors, each second bitslice vector corresponding to a column of the second matrix, each column of the second matrix having the number of n-bit operands; provides the first bitslice vector as the first input to an array of single-bit dot product units; provides the second bit-slice tensor as the second input to the array of single-bit dot product units; and obtains, from the array of single-bit dot product units, an output comprising a product of the multiplication of the first and second matrices.

In another embodiment of the processor, each first bitslice vector is provided as the first input to each single bit dot product unit in one row of the array of single bit dot product units; and each second bitslice vector is provided as the second input to each single bit dot product unit in one column of the array of single bit dot product units.

In one embodiment, a computer-based method for performing matrix multiplication includes, at a processor, obtaining a first bitslice vector comprising m elements, where each element is a bit vector having a plurality of bits, where each bit corresponds to a bit value at a particular bit position of a respective m-bit operand of a number of m-bit operands; obtaining a second bitslice vector comprising n elements, where each element is a bit vector having a plurality of bits, where each bit corresponds to a bit value at a particular bit position of a respective n-bit operand of a number of n-bit operands, where n and m are greater than one; providing at least one element of the first bitslice vector as a first input to a single-bit dot product unit; providing at least one element of the second bit-slice vector as a second input to the single-bit dot product unit; and obtaining, from the single-bit dot product unit, an output comprising at least a partial dot product of the first and second bitslice vectors.

In another embodiment of the computer-based method, providing at least one element of the first bitslice vector includes providing the elements of the first bitslice vector in a first sequence; providing at least one element of the second bitslice vector includes providing the elements of the second bitslice vector in a second sequence; and the output is a dot product of the first and second bitslice vectors.

In another embodiment of the computer-based method, obtaining the first bit-slice vector includes reading the first bit vector from a storage; and obtaining the second bit-slice vector includes reading the second bit vector from the storage.

In another embodiment of the computer-based method, obtaining the first bit-slice vector includes for each m-bit operand, generating a bit vector having m bits, each bit corresponding to a bit value at a particular bit position of the m-bit operand, and generating the first bitslice vector based on the bit vectors for the m bit operands; and obtaining the second bit-slice vector includes for each n-bit operand, generating a bit vector having n bits, each bit corresponding to a bit value at a particular bit position of the n-bit operand, and generating the second bitslice vector based on the bit vectors for the n bit operands.

In another embodiment of the computer-based method, the number of m bit operands is the same as the number of n-bit operands.

In another embodiment of the computer-based method, m is less than n.

In another embodiment of the computer-based method, the method further includes, at the processor, obtaining a first bitslice tensor based on a first matrix, the first bitslice tensor including a number of first bitslice vectors, each first bitslice vector corresponding to a row of the first matrix, each row of the first matrix having the number of m-bit operands; obtaining a second bitslice tensor based on a second matrix, the second bitslice tensor including a number of second bitslice vectors, each second bitslice vector corresponding to a column of the second matrix, each column of the second matrix having the number of n-bit operands; providing the first bitslice vector as a first input to an array of single-bit dot product units; providing the second bit-slice tensor as the second input to the array of single-bit dot product units; and obtaining, from the array of single-bit dot product units, an output comprising a product of the multiplication of the first and second matrices.

In another embodiment of the computer-based method, each first bitslice vector is provided as the first input to each single bit dot product unit in one row of the array of single bit dot product units; and each second bitslice vector is provided as the second input to each single bit dot product unit in one column of the array of single bit dot product units.

In one embodiment, an apparatus includes a processor configured to obtain a first bitslice vector comprising m elements, where each element is a bit vector having a plurality of bits, where each bit corresponds to a bit value at a particular bit position of a respective m-bit operand of a number of m-bit operands, and obtain a second bitslice vector comprising n elements, where each element is a bit vector having a plurality of bits, where each bit corresponds to a bit value at a particular bit position of a respective n-bit operand of a number of n-bit operands, where n and m are greater than one; and a single-bit dot product unit configured to receive at least one element of the first bitslice vector as a first input, receive at least one element of the second bit-slice vector as a second input, and generate an output comprising at least a partial dot product of the first and second bitslice vectors.

In another embodiment of the apparatus, the single-bit dot product unit includes a first circuit configured to input a first operand, input a second operand, and output a resultant value; a second circuit configured to input an index parameter, input a sign parameter, receive the resultant value from the first circuit, and output an intermediate value based on the index parameter, the sign parameter and the resultant value; a third circuit configured to receive the intermediate value from the second circuit, and add the intermediate value to an accumulated value; and an accumulation storage configured to store the accumulated value, and output a final accumulated value as a dot product.

In another embodiment of the apparatus, the first operand is an element of the first bitslice vector having an index j equal to the associated bit position of the element; the second operand is an element of the second bitslice vector having an index k equal to the associated bit position of the element; the second circuit is configured to count a number of bits set to one in the resultant value to generate a population count value, left-shift the population count value based on the index parameter to generate the intermediate value, and multiply the intermediate value by the sign parameter; and the index parameter is equal to j+k.

In another embodiment of the apparatus, when the m-bit and n-bit operands are unsigned elements, the sign parameter is equal to 1; and when the m-bit and n-bit operands are signed elements, the sign parameter is equal to 1 or −1, based on the index j and the index k.

While implementations of the disclosure are susceptible to embodiment in many different forms, there is shown in the drawings and will herein be described in detail specific embodiments, with the understanding that the present disclosure is to be considered as an example of the principles of the disclosure and not intended to limit the disclosure to the specific embodiments shown and described. In the description above, like reference numerals may be used to describe the same, similar or corresponding parts in the several views of the drawings.

In this document, relational terms such as first and second, top and bottom, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. The terms “comprises,” “comprising,” “includes,” “including,” “has,” “having,” or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element preceded by “comprises . . . a” does not, without more constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element.

Reference throughout this document to “one embodiment,” “certain embodiments,” “an embodiment,” “implementation(s),” “aspect(s),” or similar terms means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present disclosure. Thus, the appearances of such phrases or in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments without limitation.

The term “or” as used herein is to be interpreted as an inclusive or meaning any one or any combination. Therefore, “A, B or C” means “any of the following: A; B; C; A and B; A and C; B and C; A, B and C.” An exception to this definition will occur only when a combination of elements, functions, steps or acts are in some way inherently mutually exclusive. Also, grammatical conjunctions are intended to express any and all disjunctive and conjunctive combinations of conjoined clauses, sentences, words, and the like, unless otherwise stated or clear from the context. Thus, the term “or” should generally be understood to mean “and/or” and so forth. References to items in the singular should be understood to include items in the plural, and vice versa, unless explicitly stated otherwise or clear from the text.

Recitation of ranges of values herein are not intended to be limiting, referring instead individually to any and all values falling within the range, unless otherwise indicated, and each separate value within such a range is incorporated into the specification as if it were individually recited herein. The words “about,” “approximately,” or the like, when accompanying a numerical value, are to be construed as indicating a deviation as would be appreciated by one of ordinary skill in the art to operate satisfactorily for an intended purpose. Ranges of values and/or numeric values are provided herein as examples only, and do not constitute a limitation on the scope of the described embodiments. The use of any and all examples, or exemplary language (“e.g.,” “such as,” “for example,” or the like) provided herein, is intended merely to better illuminate the embodiments and does not pose a limitation on the scope of the embodiments. No language in the specification should be construed as indicating any unclaimed element as essential to the practice of the embodiments.

For simplicity and clarity of illustration, reference numerals may be repeated among the figures to indicate corresponding or analogous elements. Numerous details are set forth to provide an understanding of the embodiments described herein. The embodiments may be practiced without these details. In other instances, well-known methods, procedures, and components have not been described in detail to avoid obscuring the embodiments described. The description is not to be considered as limited to the scope of the embodiments described herein.

In the following description, it is understood that terms such as “first,” “second,” “top,” “bottom,” “up,” “down,” “above,” “below,” and the like, are words of convenience and are not to be construed as limiting terms. Also, the terms apparatus, device, system, etc. may be used interchangeably in this text.

The many features and advantages of the disclosure are apparent from the detailed specification, and, thus, it is intended by the appended claims to cover all such features and advantages of the disclosure which fall within the scope of the disclosure. Further, since numerous modifications and variations will readily occur to those skilled in the art, it is not desired to limit the disclosure to the exact construction and operation illustrated and described, and, accordingly, all suitable modifications and equivalents may be resorted to that fall within the scope of the disclosure. 

What is claimed is:
 1. A processor for performing matrix multiplication, the processor to: obtain a first bitslice vector comprising m elements, where each element is a bit vector having a plurality of bits, where each bit corresponds to a bit value at a particular bit position of a respective m-bit operand of a number of m-bit operands; obtain a second bitslice vector comprising n elements, where each element is a bit vector having a plurality of bits, where each bit corresponds to a bit value at a particular bit position of a respective n-bit operand of a number of n-bit operands, where n and m are greater than one; provide at least one element of the first bitslice vector as a first input to a single-bit dot product unit; provide at least one element of the second bit-slice vector as a second input to the single-bit dot product unit; and obtain, from the single-bit dot product unit, an output comprising at least a partial dot product of the first and second bitslice vectors.
 2. The processor according to claim 1, where: said provide at least one element of the first bitslice vector includes provide the elements of the first bitslice vector in a first sequence; said provide at least one element of the second bitslice vector includes provide the elements of the second bitslice vector in a second sequence; and the output is a dot product of the first and second bitslice vectors.
 3. The processor according to claim 2, where: said obtain the first bit-slice vector includes read the first bit vector from a storage; and said obtain the second bit-slice vector includes read the second bit vector from the storage.
 4. The processor according to claim 2, where: said obtain the first bit-slice vector includes: for each m-bit operand, generate a bit vector having m bits, each bit corresponding to a bit value at a particular bit position of the m-bit operand, and generate the first bitslice vector based on the bit vectors for the m-bit operands; and said obtain the second bit-slice vector includes: for each n-bit operand, generate a bit vector having n bits, each bit corresponding to a bit value at a particular bit position of the n-bit operand, and generate the second bitslice vector based on the bit vectors for the n-bit operands.
 5. The processor according to claim 4, where the number of m-bit operands is the same as the number of n-bit operands.
 6. The processor according to claim 5, where m is less than n.
 7. The processor according to claim 5, the processor to: obtain a first bitslice tensor based on a first matrix, the first bitslice tensor including a number of first bitslice vectors, each first bitslice vector corresponding to a row of the first matrix, each row of the first matrix having the number of m-bit operands; obtain a second bitslice tensor based on a second matrix, the second bitslice tensor including a number of second bitslice vectors, each second bitslice vector corresponding to a column of the second matrix, each column of the second matrix having the number of n-bit operands; provide the first bitslice vector as the first input to an array of single-bit dot product units; provide the second bit-slice tensor as the second input to the array of single-bit dot product units; and obtain, from the array of single-bit dot product units, an output comprising a product of the multiplication of the first and second matrices.
 8. The processor according to claim 7, where: each first bitslice vector is provided as the first input to each single-bit dot product unit in one row of the array of single-bit dot product units; and each second bitslice vector is provided as the second input to each single-bit dot product unit in one column of the array of single-bit dot product units.
 9. A computer-based method for performing matrix multiplication, comprising: at a processor: obtaining a first bitslice vector comprising m elements, where each element is a bit vector having a plurality of bits, where each bit corresponds to a bit value at a particular bit position of a respective m-bit operand of a number of m-bit operands; obtaining a second bitslice vector comprising n elements, where each element is a bit vector having a plurality of bits, where each bit corresponds to a bit value at a particular bit position of a respective n-bit operand of a number of n-bit operands, where n and m are greater than one; providing at least one element of the first bitslice vector as a first input to a single-bit dot product unit; providing at least one element of the second bit-slice vector as a second input to the single-bit dot product unit; and obtaining, from the single-bit dot product unit, an output comprising at least a partial dot product of the first and second bitslice vectors.
 10. The processor-based method according to claim 9, where: said providing at least one element of the first bitslice vector includes providing the elements of the first bitslice vector in a first sequence; said providing at least one element of the second bitslice vector includes providing the elements of the second bitslice vector in a second sequence; and the output is a dot product of the first and second bitslice vectors.
 11. The processor-based method according to claim 10, where: said obtaining the first bit-slice vector includes reading the first bit vector from a storage; and said obtaining the second bit-slice vector includes reading the second bit vector from the storage.
 12. The processor-based method according to claim 10, where: said obtaining the first bit-slice vector includes: for each m-bit operand, generating a bit vector having m bits, each bit corresponding to a bit value at a particular bit position of the m-bit operand, and generating the first bitslice vector based on the bit vectors for the m-bit operands; and said obtaining the second bit-slice vector includes: for each n-bit operand, generating a bit vector having n bits, each bit corresponding to a bit value at a particular bit position of the n-bit operand, and generating the second bitslice vector based on the bit vectors for the n-bit operands.
 13. The processor-based method according to claim 12, where the number of m-bit operands is the same as the number of n-bit operands.
 14. The processor-based method according to claim 13, where m is less than n.
 15. The processor-based method according to claim 13, further comprising: at the processor: obtaining a first bitslice tensor based on a first matrix, the first bitslice tensor including a number of first bitslice vectors, each first bitslice vector corresponding to a row of the first matrix, each row of the first matrix having the number of m-bit operands; obtaining a second bitslice tensor based on a second matrix, the second bitslice tensor including a number of second bitslice vectors, each second bitslice vector corresponding to a column of the second matrix, each column of the second matrix having the number of n-bit operands; providing the first bitslice vector as a first input to an array of single-bit dot product units; providing the second bit-slice tensor as the second input to the array of single-bit dot product units; and obtaining, from the array of single-bit dot product units, an output comprising a product of the multiplication of the first and second matrices.
 16. The processor-based method according to claim 15, where: each first bitslice vector is provided as the first input to each single-bit dot product unit in one row of the array of single-bit dot product units; and each second bitslice vector is provided as the second input to each single-bit dot product unit in one column of the array of single-bit dot product units.
 17. An apparatus, comprising: a processor configured to: obtain a first bitslice vector comprising m elements, where each element is a bit vector having a plurality of bits, where each bit corresponds to a bit value at a particular bit position of a respective m-bit operand of a number of m-bit operands, and obtain a second bitslice vector comprising n elements, where each element is a bit vector having a plurality of bits, where each bit corresponds to a bit value at a particular bit position of a respective n-bit operand of a number of n-bit operands, where n and m are greater than one; and a single-bit dot product unit configured to: receive at least one element of the first bitslice vector as a first input, receive at least one element of the second bit-slice vector as a second input, and generate an output comprising at least a partial dot product of the first and second bitslice vectors.
 18. The apparatus according to claim 17, where the single-bit dot product unit includes: a first circuit configured to input a first operand, input a second operand, and output a resultant value; a second circuit configured to input an index parameter, input a sign parameter, receive the resultant value from the first circuit, and output an intermediate value based on the index parameter, the sign parameter and the resultant value; a third circuit configured to receive the intermediate value from the second circuit, and add the intermediate value to an accumulated value; and an accumulation storage configured to store the accumulated value, and output a final accumulated value as a dot product.
 19. The apparatus according to claim 18, where: the first operand is an element of the first bitslice vector having an index j equal to the associated bit position of the element; the second operand is an element of the second bitslice vector having an index k equal to the associated bit position of the element; the second circuit is configured to: count a number of bits set to one in the resultant value to generate a population count value, left-shift the population count value based on the index parameter to generate the intermediate value, and multiply the intermediate value by the sign parameter; and the index parameter is equal to j+k.
 20. The apparatus according to claim 19, where: when the m-bit and n-bit operands are unsigned elements, the sign parameter is equal to 1; and when the m-bit and n-bit operands are signed elements, the sign parameter is equal to 1 or −1, based on the index j and the index k. 